succession_ in time of two sensations we shall have to quote in another
chapter, makes some noteworthy remarks about the way in which the
attention must be _set_ to catch the interval and the right order of
the sensations, when the time is exceeding small. The point was to
tell whether two signals were simultaneous or successive; and, if
successive, which one of them came first.
The first way of attending which he found himself to fall into, was
when the signals did not differ greatly--when, e.g., they were similar
sounds heard each by a different ear. Here he lay in wait for the
_first_ signal, whichever it might be, and identified it the next
moment in memory. The second, which could then always be known by
default, was often not clearly distinguished in itself. When the time
was too short, the first could not be isolated from the second at all.
The second way was to accommodate the attention for a certain _sort_
of signal, and the next moment to become aware in memory of whether it
came before or after its mate.
"This way brings great uncertainty with it. The impression not
prepared for comes to us in the memory more weak than the other,
obscure as it were, badly fixed in time. We tend to take the
subjectively stronger stimulus, that which we were intent upon, for
the first, just as we are apt to take an objectively stronger stimulus
to be the first. Still, it may happen otherwise. In the experiments
from touch to sight it often seemed to me as if the impression for
which the attention was _not_ prepared were there already when the
other came."
Exner found himself employing this method oftenest when the impressions
differed strongly.[331]
In such observations (which must not be confounded with those where
the two signals were identical and their successiveness known as
mere _doubleness_, without distinction of which came first), it is
obvious that each signal must combine stably in our perception with a
_different_ instant of time. It is the simplest possible case of two
discrepant concepts simultaneously occupying the mind. Now the case of
the signals being _simultaneous_ seems of a different sort. We must
turn to Wundt for observations fit to cast a nearer light thereon.
The reader will remember the reaction-time experiments of which we
treated in Chapter III. It happened occasionally in Wundt's experiments
that the reaction-time was reduced to zero or even assumed a negative
value, which, being translated into common speech, means that the
observer was sometimes so intent upon the signal that his reaction
_actually coincided in time with it, or even preceded it,_ instead of
coming a fraction of a second after it, as in the nature of things it
should. More will be said of these results anon. Meanwhile Wundt, in
explaining them, says this:
"In general _we have a very exact feeling of the simultaneity of two
stimuli,_ if they do not differ much in strength. And in a series of
experiments in which a warning precedes, at a fixed interval, the
stimulus, we involuntarily try to react, not only as promptly as
possible, but also in such wise that our movement may coincide with
the stimulus itself. We seek to make our own feelings of touch and
innervation [muscular contraction] objectively _contemporaneous with
the signal_ which we hear; and experience shows that in many cases we
approximately succeed. In these cases we have a distinct consciousness
of hearing the signal, reacting upon it, and feeling our reaction take
place,--all at one and the same moment."[332]
In another place, Wundt adds:
"The difficulty of these observations and the comparative infrequency
with which the reaction-time can be made thus to disappear shows how
hard it is, when our attention is intense, to keep it fixed even on
_two_ different ideas at once. Note besides that when this happens,
one always tries to bring the ideas into a certain connection, to
grasp them as components of a certain complex representation. Thus in
the experiments in question, it has often seemed to me that I produced
by my own recording movement the sound which the ball made in dropping
on the board."[333]
The 'difficulty,' in the cases of which Wundt speaks, is that of
forcing two non-simultaneous events into apparent combination with
the same instant of time. There is no difficulty, as he admits, in so
dividing our attention between two _really_ simultaneous impressions
as to feel them to be such. The cases he describes are really cases
of anachronistic perception, of subjective time-displacement, to use
his own term. Still more curious cases of it have been most carefully
studied by him. They carry us a step farther in our research, so I will
quote them, using as far as possible his exact words:
"The conditions become more complicated when we receive a series
of impressions separated by distinct intervals, into the midst of
which a heterogeneous impression is suddenly brought. Then comes
the question, with which member of the series do we perceive the
additional impression to coincide? with that member with whose
presence it really coexists, or is there some aberration?... If the
additional stimulus belongs to a different sense very considerable
aberrations may occur.
"The best way to experiment is with a number of visual impressions
(which one can easily get from a moving object) for the series, and
with a sound as the disparate impression. Let, e.g., an index-hand
move over a circular scale with uniform and sufficiently slow
velocity, so that the impressions it gives will not fuse, but permit
its position at any instant to be distinctly seen. Let the clockwork
which turns it have an arrangement which rings a bell once in every
revolution, but at a point which can be varied, so that the observer
need never know in advance just when the bell-stroke takes place.
In such observations three cases are possible. The bell-stroke can
be perceived either exactly at the moment to which the index points
when it sounds--in this case there will be no time-displacement; or
we can combine it with a later position of the index--... _positive
time-displacement_, as we shall call it; or finally we can combine
it with a position of the index earlier than that at which the sound
occurred--and this we will call a _negative displacement_. The most
natural displacement would apparently be the positive, since for
apperception a certain time is always required.... But experience
shows that the opposite is the case: it happens most frequently
that the sound appears earlier than its real date--far less often
coincident with it, or later. It should be observed that in all
these experiments it takes some time to get a distinctly perceived
combination of the sound with a particular position of the index,
and that a single revolution of the latter is never enough for the
purpose. The motion must go on long enough for the sounds themselves
to form a regular series--the outcome being a simultaneous perception
of two distinct series of events, of which either may by changes in
its rapidity modify the result. The first thing one remarks is that
the sound belongs in a certain region of the scale; only gradually
is it perceived to combine with a particular position of the index.
But even a result gained by observation of many revolutions may be
deficient in certainty, for accidental combinations of attention
have a great influence upon it. If we deliberately try to combine
the bell-stroke with an arbitrarily chosen position of the index, we
succeed without difficulty, provided this position be not too remote
from the true one. If, again, we cover the whole scale, except a
single division over which we may see the index pass, we have a strong
tendency to combine the bell-stroke with this actually seen position;
and in so doing may easily overlook more than 1/4 of a second of
time. Results, therefore, to be of any value, must be drawn from
long-continued and very numerous observations, in which such irregular
oscillations of the attention neutralize each other according to the
law of great numbers, and allow the true laws to appear. Although
my own experiments extend over many years (with interruptions), they
are not even yet numerous enough to exhaust the subject--still, they
bring out the principal laws which the attention follows under such
conditions."[334]
Wundt accordingly distinguishes the _direction_ from the _amount_ of
the apparent displacement in time of the bell-stroke. The direction
depends on the rapidity of the movement of the index and (consequently)
on that of the succession of the bell-strokes. The moment at which
the bell struck was estimated by him with the least tendency to
error, when the revolutions took place once in a second. Faster than
this, _positive_ errors began to prevail; slower, _negative_ ones
almost always were present. On the other hand, if the rapidity went
_quickening_, errors became _negative_; if _slowing, positive_. The
amount of error is, in general, the greater the slower the speed and
its alterations. Finally, individual differences prevail, as well as
differences in the same individual at different times.[335]
Wundt's pupil von Tschisch has carried out these experiments on a still
more elaborate scale,[336] using, not only the single bell-stroke, but
2, 3, 4, or 5 simultaneous impressions, so that the attention had to
note the place of the index at the moment when a whole group of things
was happening. The single bell-stroke was always heard too early by
von Tschisch--the displacement was invariably 'negative.' As the other
simultaneous impressions were added, the displacement first became
zero and finally positive, i.e. the impressions were connected with a
position of the index that was too late. This retardation was greater
when the simultaneous impressions were disparate (electric tactile
stimuli on different places, simple touch-stimuli, different sounds)
than when they were all of the same sort. The increment of retardation
became relatively less with each additional impression, so that it is
probable that six impressions would have given almost the same result
as five, which was the maximum number used by Herr von T.
Wundt explains all these results by his previous observation that a
reaction sometimes antedates the signal (see above, p. 411). The mind,
he supposes, is so intent upon the bell-strokes that its 'apperception'
keeps ripening periodically after each stroke in anticipation of the
next. Its most natural rate of ripening may be faster or slower than
the rate at which the strokes come. If faster, then it hears the
stroke too early; if slower, it hears it too late. The position of
the index on the scale, meanwhile, is noted at the moment, early or
late, at which the bell-stroke is subjectively heard. Substituting
several impressions for the single bell-stroke makes the ripening of
the perception slower, and the index is seen too late. So, at least,
do I understand the explanations which Herren Wundt and v. Tschisch
give.[337]
This is all I have to say about the difficulty of having two discrepant
concepts together, and about the number of things to which we can
simultaneously attend.
THE VARIETIES OF ATTENTION.
The things to which we attend are said to _interest_ us. Our interest
in them is supposed to be the _cause_ of our attending. What makes an
object interesting we shall see presently; and later inquire in what
sense interest may cause attention. Meanwhile
Attention may be divided into kinds in various ways. It is either to
_a_) Objects of sense (sensorial attention); or to
_b_) Ideal or represented objects (intellectual attention). It is either
_c_) Immediate; or
_d_) Derived: immediate, when the topic or stimulus is interesting in
itself, without relation to anything else; derived, when it owes its
interest to association with some other immediately interesting thing.
What I call derived attention has been named 'apperceptive' attention.
Furthermore, Attention may be either
_e_) Passive, reflex, non-voluntary, effortless; or
_f_) Active and voluntary.
_Voluntary attention is always derived_; we never make an _effort_ to
attend to an object except for the sake of some _remote_ interest which
the effort will serve. But both sensorial and intellectual attention
may be either passive or voluntary.
In _passive immediate sensorial attention_ the stimulus is a
sense-impression, either very intense, voluminous, or sudden,--in which
case it makes no difference what its nature may be, whether sight,
sound, smell, blow, or inner pain,--or else it is an _instinctive_
stimulus, a perception which, by reason of its nature rather than its
mere force, appeals to some one of our normal congenital impulses and
has a directly exciting quality. In the chapter on Instinct we shall
see how these stimuli differ from one animal to another, and what most
of them are in man: strange things, moving things, wild animals, bright
things, pretty things, metallic things, words, blows, blood, etc.,
etc., etc.
Sensitiveness to immediately exciting sensorial stimuli characterizes
the attention of childhood and youth. In mature age we have generally
selected those stimuli which are connected with one or more so-called
permanent interests, and our attention has grown irresponsive to the
rest.[338] But childhood is characterized by great active energy, and
has few organized interests by which to meet new impressions and decide
whether they are worthy of notice or not, and the consequence is that
extreme mobility of the attention with which we are all familiar in
children, and which makes their first lessons such rough affairs. Any
strong sensation whatever produces accommodation of the organs which
perceive it, and absolute oblivion, for the time being, of the task in
hand. This reflex and passive character of the attention which, as a
French writer says, makes the child seem to belong less to himself than
to every object which happens to catch his notice, is the first thing
which the teacher must overcome. It never is overcome in some people,
whose work, to the end of life, gets done in the interstices of their
mind-wandering.
The passive sensorial attention is _derived_ when the impression,
without being either strong or of an instinctively exciting nature, is
connected by previous experience and education with things that are
so. These things may be called the _motives_ of the attention. The
impression draws an interest from them, or perhaps it even fuses into
a single complex object with them; the result is that it is brought
into the focus of the mind. A faint tap _per se_ is not an interesting
sound; it may well escape being discriminated from the general rumor
of the world. But when it is a signal, as that of a lover on the
window-pane, it will hardly go unperceived. Herbart writes:
"How a bit of bad grammar wounds the ear of the purist! How a false
note hurts the musician! or an offence against good manners the man
of the world! How rapid is progress in a science when its first
principles have been so well impressed upon us that we reproduce them
mentally with perfect distinctness and ease! How slow and uncertain,
on the other hand, is our learning of the principles themselves, when
familiarity with the still more elementary percepts connected with the
subject has not given us an adequate predisposition!--Apperceptive
attention may be plainly observed in very small children when,
hearing the speech of their elders, as yet unintelligible to them,
they suddenly catch a single known word here and there, and repeat
it to themselves; yes! even in the dog who looks round at us when
we speak of him and pronounce his name. Not far removed is the
talent which mind-wandering school-boys display during the hours of
instruction, of noticing every moment in which the teacher tells a
story. I remember classes in which, instruction being uninteresting,
and discipline relaxed, a buzzing murmur was always to be heard,
which invariably stopped for as long a time as an anecdote lasted.
How could the boys, since they seemed to hear nothing, notice when
the anecdote began? Doubtless most of them always heard something
of the teacher's talk; but most of it had no connection with their
previous knowledge and occupations, and therefore the separate words
no sooner entered their consciousness than they fell out of it again;
but, on the other hand, no sooner did the words awaken old thoughts,
forming strongly-connected series with which the new impression easily
combined, than out of new and old together a total interest resulted
which drove the vagrant ideas below the threshold of consciousness,
and brought for a while settled attention into their place."[339]
_Passive intellectual attention_ is immediate when we follow in thought
a train of images exciting or interesting _per se_; derived, when the
images are interesting only as means to a remote end, or merely because
they are associated with something which makes them dear. Owing to the
way in which immense numbers of real things become integrated into
single objects of thought for us, there is no clear line to be drawn
between immediate and derived attention of an intellectual sort. When
absorbed in intellectual attention we may become so inattentive to
outer things as to be 'absent-minded,' 'abstracted,' or '_distraits_.'
All revery or concentrated meditation is apt to throw us into this
state.
"Archimedes, it is well known, was so absorbed in geometrical
meditation that he was first aware of the storming of Syracuse by his
own death-wound, and his exclamation on the entrance of the Roman
soldiers was: _Noli turbare circulos meos!_ In like manner Joseph
Scaliger, the most learned of men, when a Protestant student in
Paris, was so engrossed in the study of Homer that he became aware
of the massacre of St. Bartholomew, and of his own escape, only on
the day subsequent to the catastrophe. The philosopher Carneades was
habitually liable to fits of meditation so profound that, to prevent
him sinking from inanition, his maid found it necessary to feed him
like a child. And it is reported of Newton that, while engaged in his
mathematical researches, he sometimes forgot to dine. Cardan, one of
the most illustrious of philosophers and mathematicians, was once,
upon a journey, so lost in thought that he forgot both his way and
the object of his journey. To the questions of his driver whether he
should proceed, he made no answer; and when he came to himself at
nightfall, he was surprised to find the carriage at a standstill, and
directly under a gallows. The mathematician Vieta was sometimes so
buried in meditation that for hours he bore more resemblance to a dead
person than to a living, and was then wholly unconscious of everything
going on around him. On the day of his marriage the great Budæus
forgot everything in his philological speculations, and he was only
awakened to the affairs of the external world by a tardy embassy from
the marriage-party, who found him absorbed in the composition of his
_Commentarii_."[340]
The absorption may be so deep as not only to banish ordinary
sensations, but even the severest pain. Pascal, Wesley, Robert Hall,
are said to have had this capacity. Dr. Carpenter says of himself that
"he has frequently begun a lecture whilst suffering neuralgic pain
so severe as to make him apprehend that he would find it impossible
to proceed; yet no sooner has he by a determined effort fairly
launched himself into the stream of thought, than he has found himself
continuously borne along without the least distraction, until the
end has come, and the attention has been released; when the pain has
recurred with a force that has overmastered all resistance, making him
wonder how he could have ever ceased to feel it."[341]
Dr. Carpenter speaks of launching himself by a determined _effort_.
This effort characterizes what we called _active or voluntary
attention_. It is a feeling which every one knows, but which most
people would call quite indescribable. We get it in the sensorial
sphere whenever we seek to catch an impression of extreme _faintness_,
be it of sight, hearing, taste, smell, or touch; we get it whenever we
seek to _discriminate_ a sensation merged in a mass of others that are
similar; we get it whenever we _resist the attractions_ of more potent
stimuli and keep our mind occupied with some object that is naturally
unimpressive. We get it in the intellectual sphere under exactly
similar conditions: as when we strive to sharpen and make distinct
an idea which we but vaguely seem to have; or painfully discriminate
a shade of meaning from its similars; or resolutely hold fast to a
thought so discordant with our impulses that, if left unaided, it would
quickly yield place to images of an exciting and impassioned kind.
All forms of attentive effort would be exercised at once by one whom
we might suppose at a dinner-party resolutely to listen to a neighbor
giving him insipid and unwelcome advice in a low voice, whilst all
around the guests were loudly laughing and talking about exciting and
interesting things.
_There is no such thing as voluntary attention sustained for more
than a few seconds at a time._ What is called sustained voluntary
attention is a repetition of successive efforts which bring back the
topic to the mind.[342] The topic once brought back, if a congenial
one, _develops_; and if its development is interesting it engages
the attention passively for a time. Dr. Carpenter, a moment back,
described the stream of thought, once entered, as 'bearing him along.'
This passive interest may be short or long. As soon as it flags, the
attention is diverted by some irrelevant thing, and then a voluntary
effort may bring it back to the topic again; and so on, under favorable
conditions, for hours together. During all this time, however, note
that it is not an identical _object_ in the psychological sense (p.
275), but a succession of mutually related objects forming an identical
_topic_ only, upon which the attention is fixed. _No one can possibly
attend continuously to an object that does not change._
Now there are always some objects that for the time being _will not
develop_. They simply _go out_; and to keep the mind upon anything
related to them requires such incessantly renewed effort that the most
resolute Will ere long gives out and lets its thoughts follow the more
stimulating solicitations after it has withstood them for what length
of time it can. There are topics known to every man from which he shies
like a frightened horse, and which to get a glimpse of is to shun.
Such are his ebbing assets to the spendthrift in full career. But why
single out the spendthrift when to every man actuated by passion the
thought of interests which negate the passion can hardly for more than
a fleeting instant stay before the mind? It is like 'memento mori' in
the heyday of the pride of life. Nature rises at such suggestions, and
excludes them from the view:--How long, O healthy reader, can you now
continue thinking of your tomb?--In milder instances the difficulty
is as great, especially when the brain is fagged. One snatches at
any and every passing pretext, no matter how trivial or external, to
escape from the odiousness of the matter in hand. I know a person, for
example, who will poke the fire, set chairs straight, pick dust-specks
from the floor, arrange his table, snatch up the newspaper, take down
any book which catches his eye, trim his nails, waste the morning
_anyhow_, in short, and all without premeditation,--simply because the
only thing he _ought_ to attend to Is the preparation of a noonday
lesson in formal logic which he detests. Anything but _that!_
Once more, the object must change. When it is one of sight, it will
actually become invisible; when of hearing, inaudible,--if we attend
to it too unmovingly. Helmholtz, who has put his sensorial attention
to the severest tests, by using his eyes on objects which in common
life are expressly overlooked, makes some interesting remarks on this
point in his chapter on retinal rivalry.[343] The phenomenon called
by that name is this, that if we look with each eye upon a different
picture (as in the annexed stereoscopic slide), sometimes one picture,
sometimes the other, or parts of both, will come to consciousness, but
hardly ever both combined. Helmholtz now says:
"I find that I am able to attend voluntarily, now to one and now to
the other system of lines; and that then this system remains visible
alone for a certain time, whilst the other completely vanishes.
This happens, for example, whenever I try to count the lines first
of one and then of the other system.... But it is extremely hard to
chain the attention down to one of the systems for long, unless we
associate with our looking some distinct purpose which keeps the
activity of the attention perpetually renewed. Such a one is counting
the lines, comparing their intervals, or the like. An equilibrium
of the attention, persistent for any length of time, is under no
circumstances attainable. The natural tendency of attention when left
to itself is to wander to ever new things; and so soon as the interest
of its object is over, so soon as nothing new is to be noticed there,
it passes, in spite of our will, to something else. If we wish to
keep it upon one and the same object, we must seek constantly to find
out something new about the latter, especially if other powerful
impressions are attracting us away."
[Illustration: FIG. 36.]
And again criticising an author who had treated of attention as an
activity absolutely subject to the conscious will, Helmholtz writes:
"This is only restrictedly true. We move our eyes by our will; but one
without training cannot so easily execute the intention of making them
converge. At any moment, however, he can execute that of looking at a
near object, in which act convergence is involved. Now just as little
can we carry out our purpose to keep our attention steadily fixed
upon a certain object, when our interest in the object is exhausted,
and the purpose is inwardly formulated in this abstract way. _But
we can set ourselves new questions about the object, so that a new
interest in it arises, and then the attention will remain riveted._
The relation of attention to will is, then, less one of immediate than
of mediate control."
These words of Helmholtz are of fundamental importance. And if true of
sensorial attention, how much more true are they of the intellectual
variety! The _conditio sine quâ non_ of sustained attention to a given
topic of thought is that we should roll it over and over incessantly
and consider different aspects and relations of it in turn. Only in
pathological states will a fixed and ever monotonously recurring idea
possess the mind.
* * * * *
And now we can see why it is that what is called sustained attention
is the easier, the richer in acquisitions and the fresher and more
original the mind. In such minds, subjects bud and sprout and grow. At
every moment, they please by a new consequence and rivet the attention
afresh. But an intellect unfurnished with materials, stagnant,
unoriginal, will hardly be likely to consider any subject long. A
glance exhausts its possibilities of interest. Geniuses are commonly
believed to excel other men in their power of sustained attention.[344]
In most of them, it is to be feared, the so-called 'power' is of the
passive sort. Their ideas coruscate, every subject branches infinitely
before their fertile minds, and so for hours they may be rapt. _But
it is their genius making them attentive, not their attention making
geniuses of them._ And, when we come down to the root of the matter,
we see that they differ from ordinary men less in the character of
their attention than in the nature of the objects upon which it is
successively bestowed. In the genius, these form a concatenated series,
suggesting each other mutually by some rational law. Therefore we call
the attention 'sustained' and the topic of meditation for hours 'the
same.' In the common man the series is for the most part incoherent,
the objects have no rational bond, and we call the attention wandering
and unfixed.
It is probable that genius tends actually to prevent a man from
acquiring habits of voluntary attention, and that moderate intellectual
endowments are the soil in which we may best expect, here as elsewhere,
the virtues of the will, strictly so called, to thrive. But, whether
the attention come by grace of genius or by dint of will, the longer
one does attend to a topic the more mastery of it one has. And the
faculty of voluntarily bringing back a wandering attention, over
and over again, is the very root of judgment, character, and will.
No one is _compos sui_ if he have it not. An education which should
improve this faculty would be _the_ education _par excellence_. But
it is easier to define this ideal than to give practical directions
for bringing it about. The only general pedagogic maxim bearing on
attention is that the more interest the child has in advance in the
subject, the better he will attend. Induct him therefore in such a way
as to knit each new thing on to some acquisition already there; and if
possible awaken curiosity, so that the new thing shall seem to come as
an answer, or part of an answer, to a question pre-existing in his mind.
* * * * *
At present having described the varieties, let us turn to
THE EFFECTS OF ATTENTION.
Its remote effects are too incalculable to be recorded. The practical
and theoretical life of whole species, as well as of individual beings,
results from the selection which the habitual direction of their
attention involves. In Chapters XIV and XV some of these consequences
will come to light. Suffice it meanwhile that each of us literally
_chooses_, by his ways of attending to things, what sort of a universe
he shall appear to himself to inhabit.
The immediate effects of attention are to make us:
_a_) perceive--
_b_) conceive--
_c_) distinguish--
_d_) remember--
better than otherwise we could--both more successive things and each
thing more clearly. It also
(_e_) shortens 'reaction-time.'
* * * * *
_a_ and _b_. Most people would say that a sensation attended to becomes
stronger than it otherwise would be. This point is, however, not quite
plain, and has occasioned some discussion.[345] From the strength or
intensity of a sensation must be distinguished its clearness; and to
increase _this_ is, for some psychologists, the utmost that attention
can do. When the facts are surveyed, however, it must be admitted that
to some extent the relative intensity of two sensations may be changed
when one of them is attended to and the other not. Every artist knows
how he can make a scene before his eyes appear warmer or colder in
color, according to the way he sets his attention. If for warm, he soon
begins to _see_ the red color start out of everything; if for cold, the
blue. Similarly in listening for certain notes in a chord, or overtones
in a musical sound, the one we attend to sounds probably a little more
loud as well as more emphatic than it did before. When we mentally
break a series of monotonous strokes into a rhythm, by accentuating
every second or third one, etc., the stroke on which the stress of
attention is laid seems to become stronger as well as more emphatic.
The increased visibility of optical after-images and of double images,
which close attention brings about, can hardly be interpreted otherwise
than as a real strengthening of the retinal sensations themselves.
And this view is rendered particularly probable by the fact that an
imagined visual object may, if attention be concentrated upon it long
enough, acquire before the mind's eye almost the brilliancy of reality,
and (in the case of certain exceptionally gifted observers) leave a
negative after-image of itself when it passes away (see Chapter XVIII).
Confident expectation of a certain intensity or quality of impression
will often make us sensibly see or hear it in an object which really
falls far short of it. In face of such facts it is rash to say that
attention cannot make a sense-impression more intense.
But, on the other hand, the intensification which may be brought about
seems never to lead the judgment astray. As we rightly perceive and
name the same color under various lights, the same sound at various
distances; so we seem to make an analogous sort of allowance for
the varying amounts of attention with which objects are viewed; and
whatever changes of feeling the attention may bring we charge, as it
were, to the attention's account, and still perceive and conceive the
object as the same.
"A gray paper appears to us no lighter, the pendulum-beat of a clock
no louder, no matter how much we increase the strain of our attention
upon them. No one, by doing this, can make the gray paper look
white, or the stroke of the pendulum sound like the blow of a strong
hammer,--everyone, on the contrary, feels the increase as that of his
own conscious activity turned upon the thing."[346]
Were it otherwise, we should not be able to note _intensities_ by
attending to them. Weak impressions would, as Stumpf says,[347] become
stronger by the very fact of being observed.
"I should not be able to observe faint sounds at all, but only such
as appeared to me of maximal strength, or at least of a strength that
increased with the amount of my observation. In reality, however, I
can, with steadily increasing attention, follow a diminuendo perfectly
well."
The subject is one which would well repay exact experiment, if methods
could be devised. Meanwhile there is no question whatever that
attention augments the _clearness_ of all that we perceive or conceive
by its aid. But what is meant by clearness here?
* * * * *
_c. Clearness_, so far as attention produces it, _means distinction
from other things_ and _internal analysis or subdivision_. These are
essentially products of intellectual _discrimination_, involving
comparison, memory, and perception of various relations. The attention
_per se_ does not distinguish and analyze and relate. The most we can
say is that it is a condition of our doing so. And as these processes
are to be described later, the clearness they produce had better not be
farther discussed here. The important point to notice here is that it
is not attention's _immediate_ fruit.[348]
* * * * *
_d._ Whatever future conclusion we may reach as to this, we cannot deny
that _an object once attended to will remain in the memory_, whilst
one inattentively allowed to pass will leave no traces behind. Already
in Chapter VI (see pp. 163 ff.) we discussed whether certain states
of mind were 'unconscious,' or whether they were not rather states to
which no attention had been paid, and of whose passage recollection
could afterwards find no vestiges. Dugald Stewart says:[349] "The
connection between attention and memory has been remarked by many
authors." He quotes Quintilian, Locke, and Helvetius; and goes on
at great length to explain the phenomena of 'secondary automatism'
(see above, p. 114 ff.) by the presence of a mental action grown so
inattentive as to preserve no memory of itself. In our chapter on
Memory, later on, the point will come up again.
* * * * *
_e_) Under this head, the _shortening of reaction-time_, there is a
good deal to be said of Attention's effects. Since Wundt has probably
worked over the subject more thoroughly than any other investigator
and made it peculiarly his own, what follows had better, as far as
possible, be in his words. The reader will remember the method and
results of experimentation on 'reaction-time,' as given in Chapter III.
The facts I proceed to quote may also be taken as a supplement to that
chapter. Wundt writes:
"When we wait with strained attention for a stimulus, it will often
happen that instead of registering the stimulus, we react upon some
entirely different impression,--and this not through confounding the
one with the other. On the contrary, we are perfectly well aware
at the moment of making the movement that we respond to the wrong
stimulus. Sometimes even, though not so often, the latter may be
another kind of sensation altogether,--one may, for example, in
experimenting with sound, register a flash of light, produced either
by accident or design. We cannot well explain these results otherwise
than by assuming that the strain of the attention towards the
impression we expect coexists with a preparatory innervation of the
motor centre for the reaction, which innervation the slightest shock
then suffices to turn into an actual discharge. This shock may be
given by any chance impression, even by one to which we never intended
to respond. When the preparatory innervation has once reached this
pitch of intensity, the time that intervenes between the stimulus and
the contraction of the muscles which react, may become vanishingly
small."[350]
"The perception of an impression is facilitated when the impression
is preceded by a warning which announces beforehand that it is about
to occur. This case is realized whenever several stimuli follow each
other at equal intervals,--when, e.g. we note pendulum movements by
the eye, or pendulum-strokes by the ear. Each single stroke forms
here the signal for the next, which is thus met by a fully prepared
attention. The same thing happens when the stimulus to be perceived
is preceded, at a certain interval, by a single warning: the time is
always notably shortened.... I have made comparative observations on
reaction-time with and without a warning signal. The impression to be
reacted on was the sound made by the dropping of a ball on the board
of the 'drop apparatus.'... In a first series no warning preceded the
stroke of the ball; in the second, the noise made by the apparatus in
liberating the ball served as a signal.... Here are the averages of
two series of such experiments:
Height of Fall. Average. Mean Error. No. of Expts.
25 cm. {No warning 0.253 0.051 13
{Warning 0.076 0.060 17
5 cm. {No warning 0.266 0.036 14
{Warning 0.175 0.035 17
"... In a long series of experiments, (the interval between warning
and stimulus remaining the same) the reaction-time grows less and
less, and it is possible occasionally to reduce it to a vanishing
quantity (a few thousandths of a second), to zero, or even to a
negative value.[351]... The only ground that we can assign for this
phenomenon is _the preparation (vorbereitende Spannung) of the
attention_. It is easy to understand that the reaction-time should be
shortened by this means; but that it should sometimes sink to zero
and even assume negative values, may appear surprising. Nevertheless
this latter case is also explained by what happens in the simple
reaction-time experiments" just referred to, in which, "when the
strain of the attention has reached its climax, the movement we stand
ready to execute escapes from the control of on will, and we register
a wrong signal. In these other experiments, in which a warning
foretells the moment of the stimulus, it is also plain that attention
accommodates itself so exactly to the latter's reception that _no
sooner is it objectively given than it is fully apperceived, and with
the apperception the motor discharge coincides_."[352]
Usually, when the impression is fully anticipated, attention prepares
the motor centres so completely for both stimulus and reaction that
the only time lost is that of the physiological conduction downwards.
But even this interval may disappear, i.e. the stimulus and reaction
may become objectively contemporaneous; or more remarkable still,
the reaction may be discharged before the stimulus has actually
occurred.[353] Wundt, as we saw some pages back (p. 411), explains this
by the effort of the mind so to react that we may feel our own movement
and the signal which prompts it, both at the same instant. As the
execution of the movement must precede our feeling of it, so it must
also precede the stimulus, if that and our movement are to be felt at
once.
The peculiar theoretic interest of these experiments lies in their
_showing expectant attention and sensation to be continuous or
identical processes, since they may have identical motor effects_.
Although other exceptional observations show them likewise to be
continuous _subjectively_, Wundt's experiments do not: he seems never,
at the moment of reacting prematurely, to have been misled into the
belief that the real stimulus was there.
As concentrated attention accelerates perception, so, conversely,
perception of a stimulus is _retarded by anything which either baffles
or distracts the attention_ with which we await it.
"If, e.g., we make reactions on a sound in such a way that weak and
strong stimuli irregularly alternate so that the observer can never
expect a determinate strength with any certainty, the reaction-time
for _all_ the various signals is increased,--and so is the average
error. I append two examples.... In Series I a strong and a weak
sound alternated regularly, so that the intensity was each time known
in advance. In II they came irregularly.
I. _Regular Alternation._
Average Time. Average Error. No. of Expts.
Strong sound 0.116" 0.010" 18
Weak sound 0.127" 0.012" 9
II. _Irregular Alternation._
Strong sound 0.189" 0.038" 9
Weak sound 0.298" 0.076" 15
"Still greater is the increase of the time when, unexpectedly into a
series of strong impressions, a weak one is interpolated, or _vice
versâ_. In this way I have seen the time of reaction upon a sound
so weak as to be barely perceived rise to 0.4" or 0.5", and for a
strong sound to 0 25". It is also matter of general experience that a
stimulus expected in a general way, but for whose intensity attention
cannot be adapted in advance, demands a longer reaction-time. In
such cases ... the reason for the difference can only lie in the
fact that wherever a preparation of the attention is impossible, the
time of both perception and volition is prolonged. Perhaps also the
conspicuously large reaction-times which are got with stimuli so faint
as to be just perceptible may be explained by the attention tending
always to adapt itself for something more than this minimal amount
of stimulus, so that a state ensues similar to that in the case of
unexpected stimuli.... Still more than by previously unknown stimuli
is the reaction-time prolonged by _wholly unexpected_ impressions.
This is sometimes accidentally brought about, when the observer's
attention, instead of being concentrated on the coming signal, is
dispersed. It can be realized purposely by suddenly thrusting into
a long series of equidistant stimuli a much shorter interval which
the observer does not expect. The mental effect here is like that of
being startled;--often the startling is outwardly visible. The time
of reaction may then easily be lengthened to one quarter of a second
with strong signals, or with weak ones to a half-second. Slighter, but
still very noticeable, is the retardation when the experiment is so
arranged that the observer, ignorant whether the stimulus is to be an
impression of light, sound, or touch, cannot keep his attention turned
to any particular sense-organ in advance. One notices then at the same
time a peculiar unrest, as the feeling of strain which accompanies the
attention keeps vacillating between the several senses.
"Complications of another sort arise when what is registered is
an impression anticipated both in point of quality and strength,
but accompanied by other stimuli which make the concentration of
the attention difficult. The reaction-time is here always more or
less prolonged. The simplest case of the sort is where a momentary
impression is registered in the midst of another, and continuous,
sensorial-stimulation of considerable strength. The continuous
stimulus may belong to the same sense as the stimulus to be reacted
on, or to another. When it is of the same sense, the retardation it
causes may be partly due to the distraction of the attention by it,
but partly also to the fact that the stimulus to be reacted on stands
out less strongly than if alone, and practically becomes a less
intense sensation. But other factors in reality are present; for we
find the reaction-time more prolonged by the concomitant stimulation
when the stimulus is weak than when it is strong I made experiments
in which the principal impression, or signal for reaction, was a
bell-stroke whose strength could be graduated by a spring against the
hammer with a movable counterpoise. Each set of observations comprised
two series; in one of which the bell-stroke was registered in the
ordinary way, whilst in the other a toothed wheel belonging to the
chronometric apparatus made during the entire experiment a steady
noise against a metal spring. In one half of the latter series (A)
the bell-stroke was only moderately strong, so that the accompanying
noise diminished it considerably, without, however, making it
indistinguishable. In the other half (B) the bell-sound was so loud as
to be heard with perfect distinctness above the noise.
Mean. Maximum. Minimum. No. of
Experiments.
A {Without noise 0.189 0.214 0.156 21
(Bell-stroke {With noise 0.313 0.499 0.183 16
moderate) {
B {Without noise 0.158 0.206 0.133 20
(Bell-stroke {With noise 0.203 0.295 0.140 19
loud) {
"Since, in these experiments, the sound B even with noise made a
considerably stronger impression than the sound A without, we must
see in the figures a direct influence of the disturbing noise on the
process of reaction. This influence is freed from mixture with other
factors when the momentary stimulus and the concomitant disturbance
appeal to different senses. I chose, to test this, sight and hearing.
The momentary signal was an induction-spark leaping from one platinum
point to another against a dark background. The steady stimulation was
the noise above described.
Spark. Mean. Maximum. Minimum. No. of Expts.
Without noise 0.222 0.284 0.158 20
With noise 0.300 0.390 0.250 18
"When one reflects that in the experiments with one and the same sense
the relative intensity of the signal is always depressed [which by
itself is a retarding condition] the amount of retardation in these
last observations makes it probable that _the disturbing influence
upon attention is greater when the stimuli are disparate than when
they belong to the same sense_. One does not, in fact, find it
particularly hard to register immediately, when the bell rings in the
midst of the noise; but when the spark is the signal one has a feeling
of being coerced, as one turns away from the noise towards it. This
fact is immediately connected with other properties of our attention.
The effort of the latter is accompanied by various corporeal
sensations, according to the sense which is engaged. The innervation
which exists during the effort of attention is therefore probably a
different one for each sense-organ."[354]
Wundt then, after some theoretical remarks which we need not quote now,
gives a table of retardations, as follows:
Retardation.
1. Unexpected strength of impression:
_a_) Unexpectedly strong sound 0.073
_b_) Unexpectedly weak sound 0.171
2. Interference by like stimulus (sound by sound) 0.045[355]
3. Interference by unlike stimulus (light by sound) 0.078
It seems probable, from these results obtained with elementary
processes of mind, that all processes, even the higher ones of
reminiscence, reasoning, etc., whenever attention is concentrated upon
them instead of being diffused and languid, are thereby more rapidly
performed.[356]
* * * * *
Still more interesting reaction-time observations have been made by
Münsterberg. The reader will recollect the fact noted in Chapter
III (p. 93) that reaction-time is shorter when one concentrates his
attention on the expected movement than when one concentrates it on the
expected signal. Herr Münsterberg found that this is equally the case
when the reaction is no simple reflex, but can take place only after
an intellectual operation. In a series of experiments the five fingers
were used to react with, and the reacter had to use a different finger
according as the signal was of one sort or another. Thus when a word in
the nominative case was called out he used the thumb, for the dative
he used another finger; similarly adjectives, substantives, pronouns,
numerals, etc., or, again, towns, rivers, beasts, plants, elements;
or poets, musicians, philosophers, etc., were co-ordinated each with
its finger, so that when a word belonging to either of these classes
was mentioned, a particular finger and no other had to perform the
reaction. In a second series of experiments the reaction consisted
in the utterance of a word in answer to a question, such as "name an
edible fish," etc.; or "name the first drama of Schiller," etc.; or
"which is greater, Hume or Kant?" etc.; or (first naming apples and
cherries, and several other fruits) "which do you prefer, apples or
cherries?" etc.; or "which is Goethe's finest drama?" etc.; or "which
letter comes the later in the alphabet, the letter L or the first
letter of the most beautiful tree?" etc.; or "which is less, 15 or 20
_minus_ 8?"[357] etc. etc. etc. Even in this series of reactions _the
time was much quicker token the reacter turned his attention in advance
towards the answer than when he turned it towards the question_. The
shorter reaction-time was seldom more than one fifth of a second; the
longer, from four to eight times as long.
To understand such results, one must bear in mind that in these
experiments the reacter always knew in advance in a general way the
_kind_ of question which he was to receive, and consequently the
_sphere within which_ his possible answer lay.[358] In turning his
attention, therefore, from the outset towards the answer, those
brain-processes in him which were connected with this entire 'sphere'
were kept sub-excited, and the question could then discharge with a
minimum amount of lost time that particular answer out of the 'sphere'
which belonged especially to it. When, on the contrary, the attention
was kept looking towards the question exclusively and averted from
the possible reply, all this preliminary sub-excitement of motor
tracts failed to occur, and the entire process of answering had to
be gone through with _after_ the question was heard. No wonder that
the time was prolonged. It is a beautiful example of the summation
of stimulations, and of the way in which expectant attention, even
when not very strongly focalized, will prepare the motor centres, and
shorten the work which a stimulus has to perform on them, in order to
produce a given effect when it comes.
THE INTIMATE NATURE OF THE ATTENTIVE PROCESS.
We have now a sufficient number of facts to warrant our considering
this more recondite question. And two physiological processes, of which
we have got a glimpse, immediately suggest themselves as possibly
forming in combination a complete reply. I mean
1. _The accommodation or adjustment of the sensory organs_; and
2. _The anticipatory preparation from within of the ideational centres
concerned with the object to which the attention is paid._
1. The sense-organs and the bodily muscles which favor their exercise
are adjusted most energetically in sensorial attention, whether
immediate and reflex, or derived. But there are good grounds for
believing that even intellectual attention, attention to the _idea_ of
a sensible object, is also accompanied with some degree of excitement
of the sense-organs to which the object appeals. The preparation of the
ideational centres exists, on the other hand, wherever our interest in
the object--be it sensible or ideal--is _derived_ from, or in any way
connected with, other interests, or the presence of other objects, in
the mind. It exists as well when the attention thus derived is classed
as passive as when it is classed as voluntary. So that on the whole
we may confidently conclude--since in mature life we never attend to
anything without our interest in it being in some degree derived from
its connection with other objects--that _the two processes of sensorial
adjustment and ideational preparation probably coexist in all our
concrete attentive acts._
The two points must now be proved in more detail. First, as respects
the sensorial adjustment.
That it is present when we attend to _sensible_ things is obvious. When
we look or listen we accommodate our eyes and ears involuntarily, and
we turn our head and body as well; when we taste or smell we adjust
the tongue, lips, and respiration to the object; in feeling a surface
we move the palpatory organ in a suitable way; in all these acts,
besides making involuntary muscular contractions of a positive sort,
we inhibit others which might interfere with the result--we close the
eyes in tasting, suspend the respiration in listening, etc. The result
is a more or less massive organic feeling that attention is going on.
This organic feeling comes, in the way described on page 302, to be
contrasted with that of the objects which it accompanies, and regarded
as peculiarly ours, whilst the objects form the not-me. We treat it
as a sense of our _own activity_, although it comes in to us from
our organs after they are accommodated, just as the feeling of any
object does. Any object, if _immediately_ exciting, causes a reflex
accommodation of the sense-organ, and this has two results--first, the
object's increase in clearness; and second, the feeling of activity in
question. Both are sensations of an 'afferent' sort.
But in _intellectual_ attention, as we have already seen, (p. 300),
similar feelings of activity occur. Fechner was the first, I believe,
to analyze these feelings, and discriminate them from the stronger ones
just named. He writes:
"When we transfer the attention from objects of one sense to those of
another, we have an indescribable feeling (though at the same time
one perfectly determinate, and reproducible at pleasure), of altered
_direction_ or differently localized tension (_Spannung_). We feel
a strain forward in the eyes, one directed sidewise in the ears,
increasing with the degree of our attention, and changing according as
we look at an object carefully, or listen to something attentively;
and we speak accordingly of _straining the attention_. The difference
is most plainly felt when the attention oscillates rapidly between eye
and ear; and the feeling localizes itself with most decided difference
in regard to the various sense-organs, according as we wish to
discriminate a thing delicately by touch, taste, or smell.
"But now I have, when I try to vividly recall a picture of memory or
fancy, a feeling perfectly analogous to that which I experience when
I seek to apprehend a thing keenly by eye or ear; and this analogous
feeling is very differently localized. While in sharpest possible
attention to real objects (as well as to after-images) the strain
is plainly forwards, and when the attention changes from one sense
to another only alters its direction between the several external
sense-organs, leaving the rest of the head free from strain, the
case is different in memory or fancy, for here the feeling withdraws
entirely from the external sense-organs, and seems rather to take
refuge in that part of the head which the brain fills; if I wish, for
example, to recall a place or person it will arise before me with
vividness, not according as I strain my attention forwards, but rather
in proportion as I, so to speak, retract it backwards."[359]
In myself the 'backward retraction' which is felt during attention
to ideas of memory, etc., seems to be principally constituted by the
feeling of an actual rolling outwards and upwards of the eyeballs, such
as occurs in sleep, and is the exact opposite of their behavior when we
look at a physical thing. I have already spoken of this feeling on page
300.[360] The reader who doubts the presence of these organic feelings
is requested to read the whole of that passage again.
* * * * *
It has been said, however, that we may attend to an object on the
periphery of the visual field and yet not accommodate the eye for
it. Teachers thus notice the acts of children in the school-room at
whom they appear not to be looking. Women in general train their
peripheral visual attention more than men. This would be an objection
to the _invariable and universal_ presence of movements of adjustment
as ingredients of the attentive process. Usually, as is well known,
no object lying in the marginal portions of the field of vision can
catch our attention without at the same time 'catching our eye'--that
is, fatally provoking such movements of rotation and accommodation as
will focus its image on the fovea, or point of greatest sensibility.
Practice, however, enables us, _with effort_, to attend to a marginal
object whilst keeping the eyes immovable. The object under these
circumstances never becomes perfectly distinct--the place of its image
on the retina makes distinctness impossible--but (as anyone can satisfy
himself by trying) we become more vividly conscious of it than we were
before the effort was made. Helmholtz states the fact so strikingly
that I will quote his observation in full. He was trying to combine
in a single solid percept pairs of stereoscopic pictures illuminated
instantaneously by the electric spark. The pictures were in a dark box
which the spark from time to time lighted up; and, to keep the eyes
from wandering betweenwhiles, a pin-hole was pricked through the middle
of each picture, through which the light of the room came, so that
each eye had presented to it during the dark intervals a single bright
point. With parallel optical axes the points combined into a single
image; and the slightest movement of the eyeballs was betrayed by this
image at once becoming double. Helmholtz now found that simple linear
figures could, when the eyes were thus kept immovable, be perceived
as solids at a single flash of the spark. But when the figures were
complicated photographs, many successive flashes were required to grasp
their totality.
"Now it is interesting," he says, "to find that, although we keep
steadily fixating the pin-holes and never allow their combined image
to break into two, we can, nevertheless, before the spark comes, keep
our attention voluntarily turned to any particular portion we please
of the dark field, so as then, when the spark comes, to receive an
impression only from such parts of the picture as lie in this region.
In this respect, then, our attention is quite independent of the
position and accommodation of the eyes, and of any known alteration in
these organs; and free to direct itself by a conscious and voluntary
effort upon any selected portion of a dark and undifferenced field
of view. This is one of the most important observations for a future
theory of attention."[361]
Hering, however, adds the following detail:
"Whilst attending to the marginal object we must always," he says,
"_attend at the same time_ to the object directly fixated. If even for
a single instant we let the latter slip out of our mind, our eye moves
towards the former, as may be easily recognized by the after-images
produced, or by the muscular sounds heard. The case is then less
properly to be called one of translocation, than one of unusually wide
_dispersion_, of the attention, in which dispersion the largest share
still falls upon the thing directly looked at,"[362]
and consequently directly accommodated for. Accommodation exists here,
then, as it does elsewhere, and without it we should lose a part
of our sense of attentive activity. In fact, the _strain_ of that
activity (which is remarkably great in the experiment) is due in part
to unusually strong contractions of the muscles needed to keep the
eyeballs still, which produce unwonted feelings of pressure in those
organs.
* * * * *
2. But if the peripheral part of the picture in this experiment be
not physically accommodated for, what is meant by its sharing our
attention? What happens when we 'distribute' or 'disperse' the latter
upon a thing for which we remain unwilling to 'adjust'? This leads us
to that second feature in the process, the '_ideational preparation_'
of which we spoke. _The effort to attend to the marginal region of
the picture consists in nothing more nor less than the effort to form
as clear an idea as is possible of what is there portrayed._ The idea
is to come to the help of the sensation and make it more distinct. It
comes with effort, and such a mode of coming is the remaining part of
what we know as our attention's 'strain' under the circumstances.
Let us show how universally present in our acts of attention this
reinforcing imagination, this inward reproduction, this anticipatory
thinking of the thing we attend to, is.
It must as a matter of course be present when the attention is of the
intellectual variety, for the thing attended to then _is_ nothing but
an idea, an inward reproduction or conception. If then we prove ideal
construction of the object to be present in _sensorial_ attention, it
will be present everywhere. When, however, sensorial attention is at
its height, it is impossible to tell how much of the percept comes from
without and how much from within; but if we find that the _preparation_
we make for it always partly consists of the creation of an imaginary
duplicate of the object in the mind, which shall stand ready to receive
the outward impression as if in a matrix, that will be quite enough to
establish the point in dispute.
In Wundt's and Exner's experiments quoted above, the lying in wait for
the impressions, and the preparation to react, consist of nothing but
the anticipatory imagination of what the impressions or the reactions
are to be. Where the stimulus is unknown and the reaction undetermined,
time is lost, because no stable image can under such circumstances
be formed in advance. But where both nature and time of signal and
reaction are foretold, so completely does the expectant attention
consist in premonitory imagination that, as we have seen (Footnote 273;
pp. 373, 377), it may mimic the intensity of reality, or at any rate
produce reality's motor effects. It is impossible to read Wundt's and
Exner's pages of description and not to interpret the '_Apperception_'
and '_Spannung_' and other terms as equivalents of _imagination_. With
Wundt, in particular, the word _Apperception_ (which he sets great
store by) is quite interchangeable with both imagination and attention.
All three are names for the excitement from within of ideational
brain-centres, for which Mr. Lewes's name of _preperception_ seems the
best possible designation.
Where the impression to be caught is very weak, the way not to miss it
is to sharpen our attention for it by preliminary contact with it in a
stronger form.
"If we wish to begin to observe overtones, it is advisable, just
before the sound which is to be analyzed, to sound very softly the
note of which we are in search.... The piano and harmonium are well
fitted for this use, as both give overtones that are strong. Strike
upon the piano first the _g'_ [of a certain musical example previously
given in the text]; then, when its vibrations have objectively ceased,
strike powerfully the note _c_, in whose sound _g'_ is the third
overtone, and keep your attention steadily bent upon the pitch of the
just heard _g'_; you will now hear this tone sounding in the midst of
the _c_.... If you place the resonator which corresponds to a certain
overtone, for example _g'_ of the sound _c_, against your ear, and
then make the note _c_ sound, you will hear _g'_ much strengthened by
the resonator.... This strengthening by the resonator can be used to
make the naked ear attentive to the sound which it is to catch. For
when the resonator is gradually removed, the _g'_ grows weaker; but
the attention, once directed to it, holds it now more easily fast, and
the observer hears the tone _g'_ now in the natural unaltered sound of
the note with his unaided ear."[363]
Wundt, commenting on experiences of this sort, says that
"on carefully observing, one will always find that one tries first
to recall the image in memory of the tone to be heard, and that then
one hears it in the total sound. The same thing is to be noticed
in weak or fugitive visual impressions. Illuminate a drawing by
electric sparks separated by considerable intervals, and after the
first, and often after the second and third spark, hardly anything
will be recognized. But the confused image is held fast in memory;
each successive illumination completes it; and so at last we attain
to a clearer perception. The primary motive to this inward activity
proceeds usually from the outer impression itself. We hear a sound in
which, from certain associations, we suspect a certain overtone; the
next thing is to recall the overtone in memory; and finally we catch
it in the sound we hear. Or perhaps we see some mineral substance
we have met before; the impression awakens the memory-image, which
again more or less completely melts with the impression itself. In
this way every idea takes a certain time to penetrate to the focus
of consciousness. And during this time we always find in ourselves
the peculiar _feeling_ of attention.... The phenomena show that an
_adaptation_ of attention to the impression takes place. The surprise
which unexpected impressions give us is due essentially to the fact
that our attention, at the moment when the impression occurs, is not
accommodated for it. The accommodation itself is of the double sort,
relating as it does to the intensity as well as to the quality of
the stimulus. Different qualities of impression require disparate
adaptations. And we remark that our feeling of the _strain_ of our
inward attentiveness increases with every increase in the strength of
the impressions on whose perception we are intent."[364]
The natural way of conceiving all this is under the symbolic form
of a brain-cell played upon from two directions. Whilst the object
excites it from without, other brain-cells, or perhaps spiritual
forces, arouse it from within. The latter influence is the 'adaptation
of the attention.' _The plenary energy of the brain-cell demands the
co-operation of both factors:_ not when merely present, but when both
present and attended to, is the object fully perceived.
A few additional experiences will now be perfectly clear. Helmholtz,
for instance, adds this observation to the passage we quoted a while
ago concerning the stereoscopic pictures lit by the electric spark.
"These experiments," he says, "are interesting as regards the part
which attention plays in the matter of double images.... For in
pictures so simple that it is relatively difficult for me to see
them double, I can succeed in seeing them double, even when the
illumination is only instantaneous, the moment I strive to _imagine in
a lively way how they ought then to look_. The influence of attention
is here pure; for all eye movements are shut out."[365]
In another place[366] the same writer says:
"When I have before my eyes a pair of stereoscopic drawings which
are hard to combine, it is difficult to bring the lines and points
that correspond, to cover each other, and with every little motion of
the eyes they glide apart. _But if I chance to gain a lively mental
image (Anschauungsbild) of the represented solid form_ (a thing that
often occurs by lucky chance), I then move my two eyes with perfect
certainty over the figure without the picture separating again."
Again, writing of retinal rivalry, Helmholtz says:
"It is not a trial of strength between two sensations, but depends on
our fixing or failing to fix the attention. Indeed, there is scarcely
any phenomenon so well fitted for the study of the causes which are
capable of determining the attention. It is not enough to form the
conscious intention of seeing first with one eye and then with the
other; _we must form as clear a notion as possible of what we expect
to see. Then it will actually appear_."[367]
In figures 37 and 38, where the result is ambiguous, we can make the
change from one apparent form to the other by imagining strongly in
advance the form we wish to see. Similarly in those puzzles where
certain lines in a picture form by their combination an object that has
no connection with what the picture ostensibly represents; or indeed in
every case where an object is inconspicuous and hard to discern from
the background; we may not be able to see it for a long time; but,
having once seen it, we can attend to it again whenever we like, on
account of the mental duplicate of it which our imagination now bears.
In the meaningless French words '_pas de lieu Rhône que nous_,' who
can recognize immediately the English 'paddle your own canoe'?[368]
But who that has once noticed the identity can fail to have it arrest
his attention again? When watching for the distant clock to strike,
our mind is so filled with its image that at every moment we think
we hear the longed-for or dreaded sound. So of an awaited footstep.
Every stir in the wood is for the hunter his game; for the fugitive
his pursuers. Every bonnet in the street is momentarily taken by the
lover to enshroud the head of his idol. The image in the mind _is_ the
attention; the _preperception_, as Mr. Lewes calls it, is half of the
perception of the looked-for thing.[369]
[Illustration: FIGS. 37 & 38.]
It is for this reason that men have no eyes but for those aspects of
things which they have already been taught to discern. Any one of us
can notice a phenomenon after it has once been pointed out, which not
one in ten thousand could ever have discovered for himself. Even in
poetry and the arts, some one has to come and tell us what aspects we
may single out, and what effects we may admire, before our æsthetic
nature can 'dilate' to its full extent and never 'with the wrong
emotion.' In kindergarten instruction one of the exercises is to make
the children see how many features they can point out in such an object
as a flower or a stuffed bird. They readily name the features they
know already, such as leaves, tail, bill, feet. But they may look for
hours without distinguishing nostrils, claws, scales, etc., until their
attention is called to these details; thereafter, however, they see
them every time. In short, _the only things which we commonly see are
those which we preperceive_. and the only things which we preperceive
are those which have been labelled for us, and the labels stamped into
our mind. If we lost our stock of labels we should be intellectually
lost in the midst of the world.
* * * * *
Organic adjustment, then, and ideational preparation or preperception
are concerned in all attentive acts. An interesting theory is defended
by no less authorities than Professors Bain[370] and Ribot,[371] and
still more ably advocated by Mr. N. Lange,[372] who will have it
that the ideational preparation itself is a consequence of muscular
adjustment, so that the latter may be called the essence of the
attentive process throughout. This at least is what the theory of these
authors practically amounts to, though the former two do not state it
in just these terms. The proof consists in the exhibition of cases of
intellectual attention which organic adjustment accompanies, or of
objects in thinking which we have to execute a movement. Thus Lange
says that when he tries to imagine a certain colored circle, he finds
himself first making with his eyes the movement to which the circle
corresponds, and _then_ imagining the color, etc., as a consequence of
the movement.
"Let my reader," he adds, "close his eyes and think of an extended
object, for instance a _pencil_. He will easily notice that he first
makes a slight movement [of the eyes] corresponding to the straight
line, and that he often gets a weak feeling of innervation of the hand
as if touching the pencil's surface. So, in thinking of a certain
sound, we turn towards its direction or repeat muscularly its rhythm,
or articulate an imitation of it."[373]
But it is one thing to point out the presence of muscular contractions
as constant concomitants of our thoughts, and another thing to
say, with Herr Lange, that thought is _made possible_ by muscular
contraction alone. It may well be that where the object of thought
consists of two parts, one perceived by movement and another not, the
part perceived by movement is habitually called up first and fixed
in the mind by the movement's execution, whilst the other part comes
secondarily as the movement's mere associate. But even were this the
rule with all men (which I doubt[374]), it would only be a practical
habit, not an ultimate necessity. In the chapter on the Will we shall
learn that movements themselves are results of images coming before the
mind, images sometimes of feelings in the moving part, sometimes of the
movement's effects on eye and ear, and sometimes (if the movement be
originally reflex or instinctive), of its natural stimulus or exciting
cause. It is, in truth, contrary to all wider and deeper analogies to
deny that any quality of feeling whatever can directly rise up in the
form of an idea, and to assert that only ideas of movement can call
other ideas to the mind.
So much for adjustment and preperception. The only third process I can
think of as always present is the inhibition of irrelevant movements
and ideas. This seems, however, to be a feature incidental to voluntary
attention rather than the essential feature of attention at large,[375]
and need not concern us particularly now. Noting merely the intimate
connection which our account so far establishes between attention,
on the one hand, and imagination, discrimination, and memory, on the
other, let us draw a couple of practical inferences, and then pass to
the more speculative problem that remains.
* * * * *
The practical inferences are pedagogic. First, _to strengthen attention
in children_ who care nothing for the subject they are studying and
let their wits go wool-gathering. The interest here must be 'derived'
from something that the teacher associates with the task, a reward or a
punishment if nothing less external comes to mind. Prof. Ribot says:
"A child refuses to read; he is incapable of keeping his mind fixed
on the letters, which have no attraction for him; but he looks with
avidity upon the pictures contained in a book. 'What do they mean?'
he asks. The father replies: 'When you can read, the book will tell
you.' After several colloquies like this, the child resigns himself
and falls to work, first slackly, then the habit grows, and finally
he shows an ardor which has to be restrained. This is a case of the
genesis of voluntary attention. An artificial and indirect desire has
to be grafted on a natural and direct one. Reading has no immediate
attractiveness, but it has a borrowed one, and that is enough. The
child is caught in the wheelwork, the first step is made."
I take another example, from M. B. Perez:[376]
"A child of six years, habitually prone to mind-wandering, sat down
one day to the piano of his own accord to repeat an air by which his
mother had been charmed. His exercises lasted an hour. The same child
at the age of seven, seeing his brother busy with tasks in vacation,
went and sat at his father's desk. 'What are you doing there?' his
nurse said, surprised at so finding him. 'I am,' said the child,
'learning a page of German; it isn't very amusing, but it is for an
agreeable surprise to mamma.'"
Here, again, a birth of voluntary attention, grafted this time on a
sympathetic instead of a selfish sentiment like that of the first
example. The piano, the German, awaken no spontaneous attention; but
they arouse and maintain it by borrowing a force from elsewhere.[377]
Second, take that mind-wandering which at a later age may trouble us
_whilst reading or listening to a discourse_. If attention be the
reproduction of the sensation from within, the habit of reading not
merely with the eye, and of listening not merely with the ear, but of
articulating to one's self the words seen or heard, ought to deepen
one's attention to the latter. Experience shows that this is the
case. I can keep my wandering mind a great deal more closely upon a
conversation or a lecture if I actively re-echo to myself the words
than if I simply hear them; and I find a number of my students who
report benefit from voluntarily adopting a similar course.[378]
Second, _a teacher who wishes to engage the attention of his class
must knit his novelties on to things of which they already have
preperceptions_. The old and familiar is readily attended to by
the mind and helps to hold in turn the new, forming, in Herbartian
phraseology, an '_Apperceptionsmasse_' for it. Of course it is in every
case a very delicate problem to know what 'Apperceptionsmasse' to use.
Psychology can only lay down the general rule.
IS VOLUNTARY ATTENTION A RESULTANT OR A FORCE?
When, a few pages back, I symbolized the 'ideational preparation'
element in attention by a brain-cell played upon from within, I added
'by other brain-cells, or by some spiritual force,' without deciding
which. The question 'which?' is one of those central psychologic
mysteries which part the schools. When we reflect that the turnings
of our attention form the nucleus of our inner self; when we see (as
in the chapter on the Will we shall see) that volition is nothing but
attention; when we believe that our autonomy in the midst of nature
depends on our not being pure effect, but a cause,--
_Principium quoddam quod fati fœdera rumpat,_
_Ex infinito ne causant causa sequatur--_
we must admit that the question whether attention involve such a
principle of spiritual activity or not is metaphysical as well as
psychological, and is well worthy of all the pains we can bestow on its
solution. It is in fact the pivotal question of metaphysics, the very
hinge on which our picture of the world shall swing from materialism,
fatalism, monism, towards spiritualism, freedom, pluralism,--or else
the other way.
It goes back to the automaton-theory. If feeling is an inert
accompaniment, then of course the brain-cell can be played upon only
by other brain-cells, and the attention which we give at any time
to any subject, whether in the form of sensory adaptation or of
'preperception,' is the fatally predetermined _effect_ of exclusively
material laws. If, on the other hand, the feeling which coexists with
the brain-cells' activity reacts dynamically upon that activity,
furthering or checking it, then the attention is in part, at least,
a _cause_. It does not necessarily follow, of course, that this
reactive feeling should be 'free' in the sense of having its amount
and direction undetermined in advance, for it might very well be
predetermined in all these particulars. If it were so, our attention
would not be _materially_ determined, nor yet would it be 'free' in the
sense of being spontaneous or unpredictable in advance. The question is
of course a purely speculative one, for we have no means of objectively
ascertaining whether our feelings react on our nerve-processes or not;
and those who answer the question in either way do so in consequence
of general analogies and presumptions drawn from other fields. As mere
_conceptions_, the effect-theory and the cause-theory of attention are
equally clear; and whoever affirms either conception to be true must do
so on metaphysical or universal rather than on scientific or particular
grounds.
* * * * *
As regards _immediate sensorial attention_ hardly any one is tempted to
regard it as anything but an effect.[379] We are 'evolved' so as to
respond to special stimuli by special accommodative acts which produce
clear perceptions on the one hand in us, and on the other hand such
feelings of inner activity as were above described. The accommodation
and the resultant feeling _are_ the attention. We don't bestow it, the
object draws it from us. The object has the initiative, not the mind.
_Derived attention, where there is no voluntary effort, seems also
most plausibly to be a mere effect._ The object again takes the
initiative and draws our attention to itself, not by reason of its
own intrinsic interest, but because it is connected with some other
interesting thing. Its brain-process is connected with another that is
either excited, or tending to be excited, and the liability to share
the excitement and become aroused is the liability to 'preperception'
in which the attention consists. If I have received an insult, I may
not be actively thinking of it all the time, yet the thought of it
is in such a state of heightened irritability, that the place where
I received it or the man who inflicted it cannot be mentioned in my
hearing without my attention bounding, as it were, in that direction,
as the imagination of the whole transaction revives. Where such a
stirring-up occurs, organic adjustment must exist as well, and the
ideas must innervate to some degree the muscles. Thus the whole process
of involuntary derived attention is accounted for if we grant that
there is something interesting enough to arouse and fix the thought
of whatever may be connected with it. This fixing _is_ the attention;
and it carries with it a vague sense of activity going on, and of
acquiescence, furtherance, and adoption, which makes us feel the
activity to be our own.
This reinforcement of ideas and impressions by the pre-existing
contents of the mind was what Herbart had in mind when he gave the name
of _apperceptive_ attention to the variety we describe. We easily see
now why the lover's tap should be heard--it finds a nerve-centre half
ready in advance to explode. We see how we can attend to a companion's
voice in the midst of noises which pass unnoticed though objectively
much louder than the words we hear. Each word is _doubly_ awakened;
once from without by the lips of the talker, but already before that
from within by the premonitory processes irradiating from the previous
words, and by the dim arousal of all processes that are connected with
the 'topic' of the talk. The irrelevant noises, on the other hand, are
awakened only once. They form an unconnected train. The boys at school,
inattentive to the teacher except when he begins an anecdote, and then
all pricking up their ears, are as easily explained. The words of the
anecdote shoot into association with exciting objects which react and
fix them; the other words do not. Similarly with the grammar heard by
the purist and Herbart's other examples quoted on page 418.
Even where the attention is voluntary, it is possible to conceive of
it as an effect, and not a cause, a product and not an agent. The
things we attend to _come to us_ by their own laws. Attention _creates_
no idea; an idea must already be there before we can attend to it.
Attention only fixes and retains what the ordinary laws of association
bring 'before the footlights' of consciousness. But the moment we admit
this we see that the attention _per se_, the _feeling_ of attending
need no more fix and retain the ideas than it need bring them. The
associates which bring them also fix them by the interest which they
lend. In short, voluntary and involuntary attention may be essentially
the same. It is true that where the ideas are intrinsically very
unwelcome and the effort to attend to them is great, it seems to us
as if the frequent renewal of the effort were the very cause by which
they are held fast, and we naturally think of the effort as an original
force. In fact it is only to the _effort to attend_, not to the mere
_attending_, that we are seriously tempted to ascribe spontaneous
power. We think we can make more of it _if we will_; and the amount
which we make does not seem a fixed function of the ideas themselves,
as it would necessarily have to be if our effort were an effect and not
a spiritual force. But even here it is possible to conceive the facts
mechanically and to regard the effort as a mere effect.
Effort is felt only where there is a conflict of interests in the
mind. The idea A may be intrinsically exciting to us. The idea Z may
derive its interest from association with some remoter good. A may
be our sweetheart, Z may be some condition of our soul's salvation.
Under these circumstances, if we succeed in attending to Z at all it
is always with expenditure of effort. The 'ideational preparation,'
the 'preperception' of A keeps going on of its own accord, whilst
that of Z needs incessant pulses of voluntary reinforcement--that
is, we have the _feeling_ of voluntary reinforcement (or effort) at
each successive moment in which the thought of Z flares brightly up
in our mind. Dynamically, however, that may mean only this: that the
associative processes which make Z triumph are really the stronger, and
in A's absence would make us give a 'passive' and unimpeded attention
to Z; but, so long as A is present, some of of their force is used to
inhibit the processes concerned with A. Such inhibition is a partial
neutralization of the brain-energy which would otherwise be available
for fluent thought. But what is lost for thought is converted into
feeling, in this case into the peculiar feeling of effort, difficulty,
or strain.
The stream of our thought is like a river. On the whole easy simple
flowing predominates in it, the drift of things is with the pull of
gravity, and effortless attention is the rule. But at intervals an
obstruction, a set-back, a log-jam occurs, stops the current, creates
an eddy, and makes things temporarily move the other way. If a real
river could feel, it would feel these eddies and set-backs as places
of effort. "I am here flowing," it would say, "in the direction of
greatest resistance, instead of flowing, as usual, in the direction of
least. My effort is what enables me to perform this feat." Really, the
effort would only be a passive index that the feat was being performed.
The agent would all the while be the total downward drift of the rest
of the water, forcing _some_ of it upwards in this spot; and although,
_on the average_, the direction of least resistance is downwards, that
would be no reason for its not being upwards now and then. Just so with
our voluntary acts of attention. They are momentary arrests, coupled
with a peculiar feeling, of portions of the stream. But the arresting
force, instead of being this peculiar feeling itself, may be nothing
but the processes by which the collision is produced. The feeling of
effort may be 'an accompaniment,' as Mr. Bradley says, 'more or less
superfluous,' and no more contribute to the result than the pain in a
man's finger, when a hammer falls on it, contributes to the hammer's
weight. Thus the notion that our effort in attending is an original
faculty, a force additional to the others of which brain and mind are
the seat, may be an abject superstition. Attention may have to go, like
many a faculty once deemed essential, like many a verbal phantom, like
many an idol of the tribe. It may be an excrescence on Psychology. No
need of it to drag ideas before consciousness or fix them, when we see
how perfectly they drag and fix each other there.
* * * * *
I have stated the effect-theory as persuasively as I can.[380] It
is a clear, strong, well-equipped conception, and like all such, is
fitted to carry conviction, where there is no contrary proof. The
feeling of effort certainly _may_ be an inert accompaniment and not the
active element which it seems. No measurements are as yet performed
(it is safe to say none ever will be performed) which can show that
it contributes energy to the result. We _may_ then regard attention
as a superfluity, or a 'Luxus,' and dogmatize against its causal
function with no feeling in our hearts but one of pride that we are
applying Occam's razor to an entity that has multiplied itself 'beyond
necessity.'
But Occam's razor, though a very good rule of method, is certainly no
law of nature. The laws of stimulation and of association may well
be indispensable actors in all attention's performances, and may
even be a good enough 'stock-company' to carry on many performances
without aid; and yet they _may_ at times simply form the background
for a 'star-performer,' who is no more their 'inert accompaniment' or
their 'incidental product' than Hamlet is Horatio's and Ophelia's.
Such a star-performer would be the voluntary effort to attend, if it
were an original psychic force. Nature _may_, I say, indulge in these
complications; and the conception that she has done so in this case
is, I think, just as clear (if not as 'parsimonious' logically) as the
conception that she has not. To justify this assertion, _let us ask
just what the effort to attend would effect if it were an original
force_.
It would deepen and prolong the stay in consciousness of innumerable
ideas which else would fade more quickly away. The delay thus gained
might not be more than a second in duration--but that second might be
_critical_; for in the constant rising and falling of considerations
in the mind, where two associated systems of them are nearly in
equilibrium it is often a matter of but a second more or less of
attention at the outset, whether one system shall gain force to occupy
the field and develop itself, and exclude the other, or be excluded
itself by the other. When developed, it may make us act; and that act
may seal our doom. When we come to the chapter on the Will, we shall
see that the whole drama of the voluntary life hinges on the amount
of attention, slightly more or slightly less, which rival motor ideas
may receive. But the whole feeling of reality, the whole sting and
excitement of our voluntary life, depends on our sense that in it
things are _really being decided_ from one moment to another, and that
it is not the dull rattling off of a chain that was forged innumerable
ages ago. This appearance, which makes life and history tingle with
such a tragic zest, _may_ not be an illusion. As we grant to the
advocate of the mechanical theory that it may be one, so he must
grant to us that it may _not_. And the result is two conceptions of
possibility face to face with no facts definitely enough known to stand
as arbiter between them.
Under these circumstances, one can leave the question open whilst
waiting for light, or one can do what most speculative minds do,
that is, look to one's general philosophy to incline the beam. The
believers in mechanism do so without hesitation, and they ought not
to refuse a similar privilege to the believers in a spiritual force.
I count myself among the latter, but as my reasons are ethical they
are hardly suited for introduction into a psychological work.[381]
The last word of psychology here is ignorance, for the 'forces'
engaged are certainly too delicate and numerous to be followed in
detail. Meanwhile, in view of the strange arrogance with which the
wildest materialistic speculations persist in calling themselves
'science,' it is well to recall just what the reasoning is, by which
the effect-theory of attention is confirmed. It is an argument from
analogy, drawn from rivers, reflex actions and other material phenomena
where no consciousness _appears_ to exist at all, and extended to
cases where consciousness seems the phenomenon's essential feature.
_The consciousness doesn't count,_ these reasoners say; it doesn't
exist for science, it is _nil_; you mustn't think about it at all. The
intensely reckless character of all this needs no comment. It is making
the mechanical theory true _per fas aut nefas_. For the sake of that
theory we make inductions from phenomena to others that are startlingly
_unlike_ them; and we assume that a complication which Nature has
introduced (the presence of feeling and of effort, namely) is not
worthy of scientific recognition at all. Such conduct may conceivably
be _wise_, though I doubt it; but scientific, as contrasted with
metaphysical, it cannot seriously be called.[382]
INATTENTION.
Having spoken fully of attention, let me add a word about _inattention_.
We do not notice the ticking of the clock, the noise of the city
streets, or the roaring of the brook near the house; and even the
din of a foundry or factory will not mingle with the thoughts of its
workers, if they have been there long enough. When we first put on
spectacles, especially if they be of certain curvatures, the bright
reflections they give of the windows, etc., mixing with the field of
view, are very disturbing. In a few days we ignore them altogether.
Various entoptic images, _muscæ volitantes_, etc., although constantly
present, are hardly ever known. The pressure of our clothes and
shoes, the beating of our hearts and arteries, our breathing, certain
steadfast bodily pains, habitual odors, tastes in the mouth, etc., are
examples from other senses, of the same lapse into unconsciousness
of any too unchanging content--a lapse which Hobbes has expressed in
the well-known phrase, "_Semper idem sentire ac non sentire ad idem
revertunt_."
The cause of the unconsciousness is certainly not the mere blunting of
the sense-organs. Were the sensation important, we should notice it
well enough; and we can at any moment notice it by expressly throwing
our attention upon it,[383] provided it have not become so inveterate
that inattention to it is ingrained in our very constitution, as in the
case of the _muscæ volitantes_ the double retinal images, etc. But even
in these cases artificial conditions of observation and patience soon
give us command of the impression which we seek. The inattentiveness
must then be a habit grounded on higher conditions than mere sensorial
fatigue.
Helmholtz has formulated a general law of inattention which we shall
have to study in the next chapter but one. Helmholtz's law is that we
leave all impressions unnoticed which are valueless to us as signs by
which to _discriminate things_. At most such impressions fuse with
their consorts into an aggregate effect. The upper partial tones
which make human voices differ make them differ as wholes only--we
cannot dissociate the tones themselves. The odors which form integral
parts of the characteristic taste of certain substances, meat, fish,
cheese, butter, wine, do not come as odors to our attention. The
various muscular and tactile feelings that make up the perception of
the attributes 'wet,' 'elastic,' 'doughy,' etc., are not singled out
separately for what they are. And all this is due to an inveterate
habit we have contracted, of passing from them immediately to their
import and letting their substantive nature alone. They have formed
connections in the mind which it is now difficult to break; they are
constituents of processes which it is hard to arrest, and which differ
altogether from what the processes of catching the attention would be.
In the cases Helmholtz has in mind, not only we but our ancestors have
formed these habits. In the cases we started from, however, of the
mill-wheel, the spectacles, the factory din, the tight shoes, etc., the
habits of inattention are more recent, and the manner of their genesis
seems susceptible, hypothetically at least, of being traced.
How _can_ impressions that are not needed by the intellect be thus
shunted off from all relation to the rest of consciousness? Professor
G. E. Müller has made a plausible reply to this question, and most of
what follows is borrowed from him.[384] He begins with the fact that
"When we first come out of a mill or factory, in which we have
remained long enough to get wonted to the noise, we feel as if
something were _lacking_. Our total feeling of existence is different
from what it was when we were in the mill.... A friend writes to me:
'I have in my room a little clock which does not run quite twenty-four
hours without winding. In consequence of this, it often stops. So
soon as this happens, I notice it, whereas I naturally fail to notice
it when going. When this first began to happen, there was this
modification: I suddenly felt an undefined uneasiness or sort of void,
without being able to say what was the matter; and only after some
consideration did I find the cause in the stopping of the clock.'"
That the stopping of an unfelt stimulus may itself be felt is a
well-known fact: the sleeper in church who wakes when the sermon
ends; the miller who does the same when his wheel stands still, are
stock examples. Now (since every impression falling on the nervous
system must propagate itself somewhither), Müller suggests that
impressions which come to us when the thought-centres are preoccupied
with other matters may thereby be blocked or inhibited from invading
these centres, and may then overflow into lower paths of discharge.
And he farther suggests that if this process recur often enough, the
side-track thus created will grow so permeable as to be used, no matter
what may be going on in the centres above. In the acquired inattention
mentioned, the constant stimulus always caused disturbance _at first_;
and consciousness of it was extruded successfully only when the brain
was _strongly excited_ about other things. Gradually the extrusion
became easier, and at last automatic.
The side-tracks which thus learn to draft off the stimulations that
interfere with thought cannot be assigned with any precision. They
probably terminate in organic processes, or insignificant muscular
contractions which, when stopped by the cessation of their instigating
cause, immediately give us the feeling that something is gone from our
existence (as Müller says), or (as his friend puts it) the feeling of a
void.[385]
Müller's suggestion awakens another. It is a well-known fact that
persons striving to keep their attention on a difficult subject will
resort to movements of various unmeaning kinds, such as pacing the
room, drumming with the fingers, playing with keys or watch-chain,
scratching head, pulling mustache, vibrating foot, or what not,
according to the individual. There is an anecdote of Sir W. Scott,
when a boy, rising to the head of his class by cutting off from the
jacket of the usual head-boy a button which the latter was in the habit
of twirling in his fingers during the lesson. The button gone, its
owner's power of reciting also departed.--Now much of this activity
is unquestionably due to the overflow of emotional excitement during
anxious and concentrated thought. It drains away nerve-currents
which if pent up within the thought-centres would very likely make
the confusion there worse confounded. But may it not also be a means
of drafting off all the irrelevant sensations of the moment, and so
keeping the attention more exclusively concentrated upon its inner
task? Each individual usually has his own peculiar habitual movement of
this sort. A downward nerve-path is thus kept constantly open during
concentrated thought; and as it seems to be a law of frequent (if not
of universal) application, that incidental stimuli tend to discharge
through paths that are already discharging rather than through
others, the whole arrangement might protect the thought-centres from
interference from without. Were this the true _rationale_ of these
peculiar movements, we should have to suppose that the sensations
produced by each phase of the movement itself are also drafted off
immediately by the next phase and help to keep the circular process
agoing. I offer the suggestion for what it is worth; the connection
of the movements themselves with the continued effort of attention is
certainly a genuine and curious fact.
FOOTNOTES:
[322] Bain mentions attention in the Senses and the Intellect, p. 558,
and even gives a theory of it on pp. 370-374 of the Emotions of the
Will. I shall recur to this theory later on.
[323] "The first and most important, but also the most difficult, task
at the outset of an education is to overcome gradually the inattentive
dispersion of mind which shows itself wherever the organic life
preponderates over the intellectual. The training of animals ... must
be in the first instance based on the awakening of attention (cf.
Adrian Leonard, _Essai sur l'Education des Animaux_, Lille, 1842), that
is to say, we must seek to make them gradually perceive separately
things which, if left to themselves, would not be attended to, because
they would fuse with a great sum of other sensorial stimuli to a
confused total impression of which each separate item only darkens and
interferes with the rest. Similarly at first with the human child. The
enormous difficulties of deaf-mute- and especially of idiot-instruction
is principally due to the slow and painful manner in which we succeed
in bringing out from the general confusion of perception single items
with sufficient sharpness." (Waitz, Lehrb. d. Psychol., p. 632.)
[324] Elements, part i, chap. ii, _fin._
[325] Lectures on Metaphysics, lecture xiv.
[326] Nature, vol. iii, p. 281 (1871).
[327] If a lot of dots or strokes on a piece of paper be exhibited for
a moment to a person in _normal_ condition, with the request that he
say how many are there, he will find that they break into groups in his
mind's eye, and that whilst he is analyzing and counting one group in
his memory the others dissolve. In short, the impression made by the
dots changes rapidly into something else. In the _trance-subject_, on
the contrary, it seems to _stick_; I find that persons in the hypnotic
state easily count the dots in the mind's eye so long as they do not
much exceed twenty in number.
[328] Mr. Cattell made Jevons's experiment in a much more precise way
(Philosophische Studien, iii, 121 ff.). Cards were ruled with short
lines, varying in number from four to fifteen, and exposed to the eye
for a hundredth of a second. When the number was but four or five, no
mistakes as a rule were made. For higher numbers the tendency was to
under- rather than to over-estimate. Similar experiments were tried
with letters and figures, and gave the same result. When the letters
formed familiar words, three times as many of them could be named as
when their combination was meaningless. If the words formed a sentence,
twice as many of them could be caught as when they had no connection.
"The sentence was then apprehended as a whole. If not apprehended thus,
almost nothing is apprehended of the several words; but if the sentence
as a whole is apprehended, then the words appear very distinct."--Wundt
and his pupil Dietze had tried similar experiments on rapidly repeated
strokes of sound. Wundt made them follow each other in groups, and
found that groups of twelve strokes at most could be recognized and
identified when they succeeded each other at the most favorable rate,
namely, from three to five tenths of a second (Phys. Psych., ii, 215).
Dietze found that by mentally subdividing the groups into sub-groups
as one listened, as many as forty strokes could be identified as a
whole. They were then grasped as eight sub-groups of five, or as five
of eight strokes each. (Philosophische Studien, ii, 362.)--Later in
Wundt's Laboratory, Bechterew made observations on two _simultaneously_
elapsing series of metronome strokes, of which one contained one
stroke more than the other. The most favorable rate of succession was
0.3 sec., and he then discriminated a group of 18 from one of 18 + 1,
apparently. (Neurologisches Centralblatt, 1889, 272.)
[329] Revue Scientifique, vol. 39, p. 684 (May 28, 1887).
[330] Cf. Chr. Wolff: Psychologia Empirica, § 245. Wolff's account of
the phenomena of attention is in general excellent.
[331] Pflüger's Archiv, xi, 429-31.
[332] Physiol. Psych., 2d ed. ii, pp. 238-40.
[333] _Ib._ p. 262.
[334] Physiol. Psych., 2d ed. ii, 264-6.
[335] This was the original 'personal equation' observation of Bessel.
An Observer looked through his equatorial telescope to note the moment
at which a star crossed the meridian, the latter being marked in the
telescopic field of view by a visible thread, beside which other
equidistant threads appear. "Before the star reached the thread he
looked at the clock, and then, with eye at telescope, counted the
seconds by the beat of the pendulum. Since the star seldom passed
the meridian at the exact moment of a beat, the observer, in order
to estimate fractions, had to note its position at the stroke before
and at the stroke after the passage, and to divide the time as the
meridian-line seemed to divide the space. If, e.g., one had counted
20 seconds, and at the 21st the star seemed removed by _ac_ from the
meridian-thread _c_, whilst at the 22d it was at the distance _bc_;
then, if _ac: bc_:: 1: 2, the star would have passed at 21 1/8 seconds.
The conditions resemble those in our experiment: the star is the
index-hand, the threads are the scale; and a time-displacement is to
be expected, which with high rapidities may be positive, and negative
with low. The astronomic observations do not permit us to measure its
absolute amount; but that it exists is made certain by the fact than
after all other possible errors are eliminated, there still remains
between different observers a personal difference which is often much
larger than that between mere reaction-times, amounting ... sometimes
to more than a second." (_Op. cit._ p. 270.)
[Illustration: FIG. 35.]
[336] Philosophische Studien, ii, 601.
[337] Physiol. Psych., 2d ed. ii, 273-4; 3d ed. ii, 339; Philosophische
Studien, ii, 621 ff.--I know that I am stupid, but I confess I find
these theoretical statements, especially Wundt's, a little hazy.
Herr v. Tschisch considers it impossible that the perception of the
index's position should come in too late, and says it demands no
particular attention (p. 622). It seems, however, that this can hardly
be the case. Both observers speak of the difficulty of seeing the
index at the right moment. The case is quite different from that of
distributing the attention impartially over simultaneous momentary
sensations. The bell or other signal gives a momentary sensation, the
index a continuous one, of motion. To note any one _position_ of the
latter is to _interrupt_ this sensation of motion and to substitute an
entirely different percept--one, namely, of position--for it, during
a time however brief. This involves a sudden change in the manner of
attending to the revolutions of the index; which change _ought_ to
take place neither sooner nor later than the momentary impression, and
_fix_ the index as it is then and there visible. Now this is not a case
of simply getting two sensations at once and so feeling them--which
would be an harmonious act; but of _stopping one_ and changing it into
another, whilst we simultaneously get a third. Two of these acts are
discrepant, and the whole three rather interfere with each other. It
becomes hard to 'fix' the index at the very instant that we catch the
momentary impression; so we fall into a way of fixing it either at the
last possible moment before, or at the first possible moment after, the
impression comes.
This at least seems to me the more probable state of affairs. If we
fix the index before the impression really comes, that means that
we perceive it too late. But why do we fix it _before_ when the
impressions come slow and simple, and _after_ when they come rapid and
complex? And why under certain conditions is there no displacement
at all? The answer which suggests itself is that when there is just
enough leisure between the impressions for the attention to adapt
itself comfortably both to them and to the index (one second in W.'s
experiments), it carries on the two processes at once; when the leisure
is excessive, the attention, following its own laws of ripening, and
being _ready_ to note the index before the other impression comes,
notes it _then_, since that is the moment of easiest action, whilst
the impression, which comes a moment later, interferes with noting
it again; and finally, that when the leisure is insufficient, the
momentary impressions, being the more fixed data, are attended to
first, and the index is fixed a little later on. The noting of the
index at too early a moment would be the noting of a real fact, with
its analogue in many other rhythmical experiences. In reaction-time
experiments, for example, when, in a regularly recurring series, the
stimulus is once in a while omitted, the observer sometimes reacts
as if it came. Here, as Wundt somewhere observes, we catch ourselves
acting merely because our inward preparation is complete. The
'fixing' of the index is a sort of action; so that my interpretation
tallies with facts recognized elsewhere; but Wundt's explanation (if
I understand it) of the experiments requires us to believe that an
observer like v. Tschisch shall steadily and without exception get an
hallucination of a bell-stroke before the latter occurs, and _not hear
the real bell-stroke afterwards_. I doubt whether this is possible,
and I can think of no analogue to it in the rest of our experience.
The whole subject deserves to be gone over again. To Wundt is due
the highest credit for his patience in working out the facts. His
explanation of them in his earlier work (Vorlesungen üb. Menschen und
Thierseele, i, 37-42, 365-371) consisted merely in the appeal to the
unity of consciousness, and may be considered quite crude.
[338] Note that the permanent interests are themselves grounded in
certain objects and relations in which our interest is immediate and
instinctive.
[339] Herbart: Psychologie als Wissenschaft, § 128.
[340] Sir W. Hamilton. Metaphysics, lecture xiv.
[341] Mental Physiol., § 124. The oft-cited case of soldiers not
perceiving that they are wounded is of an analogous sort.
[342] Prof. J. M. Cattell made experiments to which we shall refer
further on, on the degree to which reaction-times might be shortened by
distracting or voluntarily concentrating the attention. He says of the
latter series that "the averages show that the attention can be kept
strained, that is, the centres kept in a state of unstable equilibrium,
for one second" (Mind, xi, 240).
[343] Physiologische Optik, § 32.
[344] "'Genius,' says Helvetius, 'is nothing but a continued attention
(_une attention suivie_).' 'Genius,' says Buffon, 'is only a protracted
patience (_une longue patience_).' 'In the exact sciences, at least,'
says Cuvier, 'it is the patience of a sound intellect, when invincible,
which truly constitutes genius.' And Chesterfield has also observed
that 'the power of applying an attention, steady and undissipated, to
a single object, is the sure mark of a superior genius.'" (Hamilton:
Lect. on Metaph., lecture xiv.)
[345] See, e.g., Ulrici: Leib u. Seele, ii, 28; Lotze: Metaphysik, §
273; Fechner, Revision d. Psychophysik, xix; G. E. Müller: Zur Theorie
d. sinnl. Aufmerksamkeit, $ 1; Stumpf: Tonpsychologie, i, 71.
[346] Fechner, _op. cit._ p. 271.
[347] Tonpsychologie, i, p. 71.
[348] Compare, on clearness as the essential fruit of attention,
Lotze's Metaphysic, § 273.
[349] Elements, part i, chap. ii.
[350] Physiol. Psych., 2d ed. ii, 226.
[351] By a negative value of the reaction-time Wundt means the case of
the reactive movement occurring _before_ the stimulus.
[352] _Op. cit._ ii, 239.
[353] The reader must not suppose this phenomenon to be of frequent
occurrence. Experienced observers, like Exner and Cattell, deny having
met with it in their personal experience.
[354] _Op. cit._ pp. 241-5.
[355] It should be added that Mr. J. M. Cattell (Mind, xi, 33) found,
on repeating Wundt's experiments with a disturbing noise upon two
practised observers, that the simple reaction-time either for light
or sound was hardly perceptibly increased. Making strong voluntary
concentration of attention shortened it by about 0.013 seconds on an
average (p. 240). Performing mental additions whilst waiting for the
stimulus lengthened it more than anything, apparently. For other,
less careful, observations, compare Obersteiner, in Brain, i, 439.
Cattell's negative results show how far some persons can abstract their
attention from stimuli by which others would be disturbed.--A. Bartels
(Versuche über die Ablenkung d. Aufmerksamkeit, Dorpat, 1889) found
that a stimulus to one eye sometimes prevented, sometimes improved, the
perception of a quickly ensuing very faint stimulus to the other.
[356] Cf. Wundt, Physiol. Psych., 1st ed. p. 794.
[357] Beiträge zur Experimentellen Psychologie, Heft i, pp. 73-106
(1889).
[358] To say the very least, he always brought his articulatory
innervation close to the discharging point. Herr M. describes a
tightening of the head-muscles as characteristic of the attitude of
attention to the reply.