LAWS AND HYPOTHESES FOR BEHAVIOR
LAWS OF BEHAVIOR IN GENERAL
_Behavior is predictable._ The first law of behavior, one fraction of
the general law of the uniformity of nature, is that with life and
mind, as with mass and motion, the same cause will produce the same
effect,—that _the same situation will, in the same animal, produce the
same response_,—and that _if the same situation produces on two occasions
two different responses, the animal must have changed_.
Scientific students of behavior will, with few exceptions, accept this
law in theory, but in practice we have not fully used it. We have too
often been content to say that a man may respond in any one of several
ways to the same situation, or may attend to one rather than another
feature of the same object, without insisting that the man must in each
case be different, and without searching for the differences in him which
cause the different reactions.
The changes in an organism which make it respond differently on different
occasions to the same situation range from temporary to permanent
changes. Hunger, fatigue, sleep, and certain diseases on the one hand,
and learning, immunity, growth and senility on the other, illustrate this
range.
Behavior is predictable _without recourse to magical agencies_. It is,
of course, the case that any given difference between the responses
of an animal to the same situation depends upon some _particular_
difference in the animal. Each immunity, for example, has its detailed
representation in an altered condition of the blood or other bodily
tissue. In general the changes in an animal which cause changes in its
behavior to the same situation are fully enumerated in a list of the
bodily changes concerned. That is, whatever changes may be supposed to
have taken place in the animal’s vital force, spiritual essence, or
other magical bases for life and thought, are useless for scientific
explanation and control of behavior.
No competent thinker probably doubts this in the case of such changes
as are referred to by hunger, sleep, fatigue, so-called ‘functional’
diseases and immunity, and those who do doubt it in the case of mental
growth and learning seem to represent an incomplete evolution from
supernatural, or rather infrascientific, thinking. There may be in
behavior a surplus beyond what would be predictable if the entire history
of every atom in the body was known—a surplus necessarily attributable to
changes in the animal’s incorporeal structure. But scientific thinkers
properly refuse to deliberately count upon such a surplus.
_Every response or change in response of an animal is then the result of
the interaction of its original knowable nature and the environment._
This may seem too self-evident a corollary for mention. It should be
so, but, unfortunately, it is not. Two popular psychological doctrines
exist in defiance of it. One is the doctrine that the movements of early
infancy are random, the original nature of the animal being entirely
indifferent as to what movement shall be made upon a given stimulus. But
no animal can have an original nature that does not absolutely prescribe
just what the response shall be to every stimulus. If the movements are
really random, they occur by virtue of some force that works at random.
If the movements are really the result of the action of the environment
on the animal’s nature, they are never random. A baby twiddles his thumbs
or waves his legs for exactly the same sort of reason that a chick pecks
at a worm or preens its wing.
The other doctrine which witnesses to neglect of the axiom that behavior
is the creation of the environment, acting on the animal’s nature, is the
doctrine that the need for a certain behavior helps to create it, that
being in a difficulty tends in and of itself to make an animal respond so
as to end the difficulty.
The truth is that to a difficulty the animal responds by whatever its
inherited and acquired nature has connected with the special form of
difficulty and that in many animals the one response of those thus
provided which relieves the difficulty is selected and connected more
firmly with that difficulty’s next appearance. The difficulty acts only
as a stimulus to the animal’s nature and its relief acts only as a
premium to the connection whereby it was relieved. The law of original
behavior, or the law of instinct, is then that _to any situation an
animal will, apart from learning, respond by virtue of the inherited
nature of its reception-, connection- and action-systems_.
The inquiry into the laws of learning to be made in this essay is limited
to those aspects of behavior which the term has come historically to
signify, that is, to intellect, skill, morals and the like.
For the purposes of this essay it is not necessary to decide just what
features of an animal’s behavior to include under intellect, skill,
morals and the like. The statements to be made will fit any reasonable
dividing line between behavior on the one side and mere circulation,
digestion, excretion and the like on the other. There should in fact
be no clear dividing line, since there is no clear gap between those
activities which naturalists have come to call behavior and the others.
The discussion will include: First, a description of two laws of
learning; second, an argument to prove that no additional forces
are needed—that these two laws explain all learning; and third, an
investigation of whether these two laws are reducible to more fundamental
laws. I shall also note briefly the consequences of the acceptance of
these laws in one sample case, that of the study of mental evolution.
PROVISIONAL LAWS OF ACQUIRED BEHAVIOR OR LEARNING
The Law of Effect is that: _Of several responses made to the same
situation, those which are accompanied or closely followed by
satisfaction to the animal will, other things being equal, be more firmly
connected with the situation, so that, when it recurs, they will be
more likely to recur; those which are accompanied or closely followed
by discomfort to the animal will, other things being equal, have their
connections with that situation weakened, so that, when it recurs, they
will be less likely to occur. The greater the satisfaction or discomfort,
the greater the strengthening or weakening of the bond._
The Law of Exercise is that: _Any response to a situation will, other
things being equal, be more strongly connected with the situation in
proportion to the number of times it has been connected with that
situation and to the average vigor and duration of the connections._
These two laws stand out clearly in every series of experiments on animal
learning and in the entire history of the management of human affairs.
They give an account of learning that is satisfactory over a wide range
of experience, so long as all that is demanded is a rough and general
means of prophecy. We can, as a rule, get an animal to learn a given
accomplishment by getting him to accomplish it, rewarding him when he
does, and punishing him when he does not; or, if reward or punishment are
kept indifferent, by getting him to accomplish it much oftener than he
does any other response to the situation in question.
For more detailed and perfect prophecy, the phrases ‘result in
satisfaction’ and ‘result in discomfort’ need further definition, and the
other things that are to be equal need comment.
By a satisfying state of affairs is meant one which the animal does
nothing to avoid, often doing such things as attain and preserve it. By a
discomforting or annoying state of affairs is meant one which the animal
commonly avoids and abandons.
The satisfiers for any animal in any given condition cannot be determined
with precision and surety save by observation. Food when hungry, society
when lonesome, sleep when fatigued, relief from pain, are samples of the
common occurrence that what favors the life of the species satisfies its
individual members. But this does not furnish a completely valid rule.
The satisfying and annoying are not synonymous with favorable and
unfavorable to the life of either the individual or the species. Many
animals are satisfied by deleterious conditions. Excitement, overeating,
and alcoholic intoxication are, for instance, three very common and very
potent satisfiers of man. Conditions useful to the life of the species
in moderation are often satisfying far beyond their useful point: many
conditions of great utility to the life of the species do not satisfy and
may even annoy its members.
The annoyers for any animal follow the rough rule that alterations
of the animal’s ‘natural’ or ‘normal’ structure—as by cuts, bruises,
blows, and the like,—and deprivations of or interference with its
‘natural’ or ‘normal’ activities,—as by capture, starvation, solitude,
or indigestion,—are intolerable. But interference with the structure
and functions by which the species is perpetuated is not a sufficient
criterion for discomfort. Nature’s adaptations are too crude.
Upon examination it appears that the pernicious states of affairs which
an animal welcomes are not pernicious _at the time, to the neurones_. We
learn many bad habits, such as morphinism, because there is incomplete
adaptation of all the interests of the body-state to the temporary
interest of its ruling class, the neurones. So also the unsatisfying
goods are not goods to the neurones at the time. We neglect many benefits
because the neurones choose their immediate advantage. The neurones must
be tricked into permitting the animal to take exercise when freezing or
quinine when in a fever, or to free the stomach from certain poisons.
Satisfaction and discomfort, welcoming and avoiding, thus seem to be
related to the maintenance and hindrance of the life processes of the
neurones rather than of the animal as a whole, and to temporary rather
than permanent maintenance and hindrance.
The chief life processes of a neurone concerned in learning are
absorption of food, excretion of waste, reception and conduction of the
nerve impulse, and modifiability or change of connections. Of these only
the latter demands comment.
The connections formed between situation and response are represented by
connections between neurones and neurones, whereby the disturbance or
neural current arising in the former is conducted to the latter across
their synapses. The strength or weakness of a connection means the
greater or less likelihood that the same current will be conducted from
the former to the latter rather than to some other place. The strength or
weakness of the connection is a condition of the synapse. What condition
of the synapse it is remains a matter for hypothesis. Close connection
might mean protoplasmic union, or proximity of the neurones in space, or
a greater permeability of a membrane, or a lowered electrical resistance,
or a favorable chemical condition of some other sort. Let us call
this undefined condition which parallels the strength of a connection
between situation and response the intimacy of the synapse. Then the
modifiability or connection changing of a neurone equals its power to
alter the intimacy of its synapses.
As a provisional hypothesis to account for what satisfies and what annoys
an animal, I suggest the following:—
A neurone modifies the intimacy of its synapses so as to keep intimate
those by whose intimacy its other life processes are favored and to
weaken the intimacy of those whereby its other life processes are
hindered. The animal’s action-system as a whole consequently does nothing
to avoid that response whereby the life processes of the neurones other
than connection-changing are maintained, but does cease those responses
whereby such life processes of the neurones are hindered.
This hypothesis has two important consequences. First: Learning by
the law of effect is then more fully adaptive for the neurones in the
changing intimacy of whose synapses learning consists, than for the
animal as a whole. It is adaptive for the animal as a whole only in so
far as his organization makes the neurones concerned in the learning
welcome states of affairs that are favorable to his life and that of his
species and reject those that are harmful.
Second: A mechanism in the neurones gives results in the behavior of
the animal as a whole that seem beyond mechanism. By their unmodifiable
abandonment of certain specific conditions and retention of others, the
animal as a whole can modify its behavior. Their one rule of conduct
causes in him a countless complexity of habits. The learning of an animal
is an instinct of its neurones.
I have limited the discussion to animals in whom the connection-system
is a differentiated organ, the neurones. In so far as the law of effect
operates in an animal whose connection-system is not anatomically
distinguishable and is favored and hindered in its life by the same
conditions that favor and hinder the life of the animal as a whole,
the satisfying and annoying will be those states of affairs which the
connection-system, whatever it be, maintains and abandons.
The other things that have to be equal in the case of the law of effect
are: First, the frequency, energy and duration of the connection,—that
is, the action of the law of exercise; second, the closeness with which
the satisfaction is associated with the response; and, third, the
readiness of the response to be connected with the situation.
The first of these accessory conditions requires no comment. A slightly
satisfying or indifferent response made often may win a closer connection
than a more satisfying response made only rarely.
The second is most clearly seen in the effect of increasing the interval
between the response and the satisfaction or discomfort. Such an increase
diminishes the rate of learning. If, for example, four boxes were
arranged so that turning a button caused a door to open (and permit a cat
to get freedom and food) in one, five, fifty and five hundred seconds,
respectively, a cat would form the habit of prompt escape from the first
box most rapidly and would almost certainly never form that habit in the
case of the fourth. The electric shock administered just as an animal
starts on the wrong path or touches the wrong mechanism, is potent, but
the same punishment administered ten or twenty seconds after an act will
have little or no effect upon that act.
Close temporal sequence is not the only means of insuring the connection
of the satisfaction with the response producing it. What is called
attention to the response counts also. If a cat pushes a button around
with its nose, while its main occupation, the act to which its general
‘set’ impels it, to which, we say, it is chiefly attentive, is that of
clawing at an opening, it will be less aided in the formation of the
habit than if it had been chiefly concerned in what its nose was doing.
The successful response is as a rule only a part of all that the animal
is doing at the time. In proportion as it is an eminent, emphatic part of
it, learning is aided. Similarly discomfort eliminates most the eminent,
emphatic features of the total response which it accompanies or shortly
follows.
The third factor, the susceptibility of the response and situation to
connection, is harder to illustrate. But, apparently, of those responses
which are equally strongly connected with a situation by nature and
equally attended to, some are more susceptible than others to a more
intimate connection.
The things which have to be equal in the case of the law of exercise
are the force of satisfyingness; that is, the action of the law of
effect, and again the readiness of the response to be connected with the
situation.
The operation of the laws of instinct, exercise and effect is
conditioned further by (1) what may be called the law of assimilation or
analogy,—that a situation, especially one to which no particular response
is connected by original nature or previous experience, may connect with
whatever response is bound to some situation _much like it_,—and (2) by
the law of partial activity—that more or less of the total situation may
be specially active in determining the response.
The first of these laws is a result of the facts that conduction in the
neurones follows the line of least resistance or closest connection, that
the action-system is so organized that certain responses tend to be made
in their totality if at all, and that slightly different situations may,
therefore, produce some one response, the effects of their differences
being in the accessories of that response.
The second law is a result of the facts that the situation, itself a
compound, produces a compound action in the neurones, and that by reason
of inner conditions, the relative intensities of different parts of the
compound may vary. The commonest response will be that due to the modal
condition of the neural compound, but every condition of the compound
will have its response.
THE ADEQUACY OF THE LAWS OF EXERCISE AND EFFECT
Behavior has been supposed to be modified in accordance with three
other principles or laws besides the law of exercise and the law of
effect. Imitation is often used as a name for the supposed law that the
perception of a certain response to a situation by another animal tends
in and of itself to connect that response to that situation. Common
acceptance has been given to more or less of the law that the idea of an
act, or of the result of an act, or of the immediate or remote sensations
produced by the act, tends in and of itself to produce the act. Such a
law of ‘suggestion’ or ‘ideo-motor’ action may be phrased differently,
but in whatever form, it insists that the bond between a situation and
some conscious representation of a response or of its consequences can do
the work of the bond between the situation and the response itself. In
acts of reasoning man has been supposed to connect with a given situation
a response that could never have been predicted merely from knowledge
of what responses were connected with that situation by his original
nature or had been connected with it by the laws of exercise and effect.
Inference has been supposed to create bonds in and of itself and to be
above the mere laws of habit.
Various forms of statement, most of them vague, have been and would be
used in describing the potency of a perceived response, a thought-of
response, or a train of inference, to produce a response and bind it to
the given total situation. Any forms will do for the present argument,
since all forms mean to assert that responses can be and often are bound
to situations otherwise than by original bodily nature, satisfaction,
discomfort, disuse and use. I shall try to show that they cannot; that,
on the contrary, the laws of exercise and effect account for all learning.
_The facts of imitation in human and animal behavior are explainable by
the laws of instinct, exercise and effect._
Some cases of imitation are undoubtedly mere instincts in which the
situation responded to is an act by another of the same species. If the
baby smiles at a smile, it is because of a special, inborn connection
between that sight and that act,—he smiles at a smile for just the same
reason that he draws down his mouth and wails at harsh words. At that
stage of his life he does not imitate other simple acts. A man runs
_with_ a crowd for the same reason that he runs _from_ a tiger. Returning
a blow is no more due to a general tendency to imitate than warding it
off is.
Other cases of imitation are mere adjuncts to the ordinary process of
habit-formation. In the first place, the act of another, or its result,
may serve as a model by which the satisfyingness of one’s own responses
are determined. Just as the touch and taste of food tells a baby that
he has got it safely into his mouth, so the sound of a word spoken by
another or the sight of another performing some act of skill tells us
whether our pronunciation or technique is right or wrong.
In the second place, the perception of another’s act may serve as a
stimulus to a response whereby the situation is altered into one to
which the animal responds from habit by an act like the one perceived.
For example, the perception of another making a certain response (_A_)
to a situation (_B_) may lead in me by the laws of habit to a response
(_C_) which puts me in a situation (_D_) such that the response (_A_) is
made by me by the laws of habit. Suppose that by previous training the
act of taking off my hat (_A_) has become connected as response to the
situation (_D_), ‘thought of hat off,’ and suppose that with the sight of
others uncovering their heads (_A_) in church (_B_) there has, again by
previous habituation, been connected, as response (_C_), ‘thought of hat
off.’ Then the sight of others uncovering their heads would by virtue of
the laws of habit lead me to uncover. Imitation of this sort, where the
perception of the act or condition in another gives rise to the idea of
performing the act or attaining the condition, the idea in turn giving
rise to the appropriate act, is certainly very common.
There may be cases of imitation which cannot be thus accounted for as
special instinctive responses to the perception of certain acts by the
same acts, as habits formed under the condition that the satisfyingness
of a response is its likeness to the perceived act of another, or as the
connection of two habits, one of getting, from the perceived act of
another, a certain inner condition, the other of getting, from this inner
condition, the act in question. There may be, that is, cases where the
perceived act of another in and of itself creates a connection.
It is apparently taken for granted by a majority of writers on human
behavior that cases of such direct mental infection, as it were, not
only exist, but are the rule. I am unable to find proof of such cases,
however. Those commonly quoted are far from clear. Learning to talk in
the human infant, for example, the stock case of imitation as a direct
means of learning, offers only very weak and dubious evidence. Since
what is true of it holds substantially for the other favored cases for
learning by imitation, I shall examine it at some length.
Let us first be clear as to the alternative explanations of linguistic
imitation. The first is that seeing the movements of another’s
mouth-parts or hearing a series of word-sounds in and of itself produces
the response of making that series of sounds or one like it.
The other is that the laws of instinct and habit are adequate to explain
the fact in the following manner: A child instinctively produces a great
variety of sounds and sound-series. Some of these, accepted as equal to
words by the child’s companions, are rewarded, so that the child learns
by the law of effect to use them in certain situations to attain certain
results. It is possible also that a child instinctively feels a special
satisfaction at babbling when spoken to and a special satisfaction at
finding the sound he makes like one that rings in the ears of memory
and has meaning. The latter would be like the instinctive satisfaction
apparently felt in constructing an object which is like some real object
whose appearance and meaning he knows.
A child also meets frequently the situations ‘say dada,’ ‘say mama,’ ‘say
good night’ and the like,[41] and is rewarded when his general babble
produces something like the word spoken to him. He thus, by the law of
effect, learns to respond to any ‘say’ situation by making _some_ sound
and to each of many ‘say’ situations by making an appropriate sound, and
to feel satisfaction at duplicating these words when heard. According
to the amount of such training, the tendency to respond to words spoken
to him by making some sound may become very strong, and the number of
successful duplications very large. Satisfaction may be so connected
with saying words that the child practices them by himself orally and
even in inner speech. The second alternative relies upon the instinct
of babbling, and the satisfaction of getting desirable effects from
speech, either the effect which the word has by its meaning as a request
(‘water,’ ‘milk,’ ‘take me outdoors’ and the like) or the effect which it
has by its mere sound upon companions who notice, pet or otherwise reward
a child for linguistic progress.
There are many difficulties in the way of accepting the first
alternative. First of all, no one can believe that _all_ of a child’s
speech is acquired by direct imitation. On many occasions the process is
undoubtedly one of the production of many sounds, irrespective of the
model given, and the selection of the best one by parental reward. Any
student who will try to get a child who is just beginning to speak, to
say cat, dog and mouse and will record the sounds actually made by the
child in the three cases, will find them very much alike. There will in
fact be little that even _looks_ like direct imitation until the child
has ‘learned’ at least forty or fifty words.
The second difficulty lies in the fact that different children, in even
the clearest cases of the imitation of one sound, vary from it in so many
directions. A list of all the sounds made in response to one sound heard
is more suggestive of random babble as modified by various habits of
duplicating sounds, than of a direct potency of the model. Ten children
of the same age may, in response to ‘Christmas,’ say, kiss, kissus,
krismus, mus, kim, kimus, kiruss, i-us and even totally unlike vocables
such as hi-yi or ya-ya.
The third difficulty is that in those features of word-sounds which are
hard to acquire, such as the ‘th’ sound, direct imitation is inadequate.
The teacher has recourse to trial and chance success, the spoken word
serving as a model to guide satisfaction and discomfort. In general no
sound not included in the instinctive babble of children seems to be
acquired by merely hearing and seeing it made.
A fourth difficulty is that by the doctrine of direct imitation it should
not be very much more than two or three times as hard to repeat a two-
or three-syllable series as to repeat a single syllable. It is, in fact,
enormously harder. This is, of course, just what is to be expected if
learning a sound means the selection from random babbling plus previous
habits. If, for instance, a child makes thirty monosyllabic sounds
like pa, ga, ta, ma, pi, gi, li, mi, etc., there is, by chance, one
chance in thirty that in response to a word or phrase he will make that
one-syllable sound of his repertory which is most like it, but there is
only one chance in nine hundred that he will make that _two-syllable_
combination of his repertory which is most like it.
On the other hand, two objections will be made to the opposite view that
the word spoken acts only as a model to select from responses otherwise
caused, or as a stimulus to habits already existing. First it will be
said that clear, indubitable repetitions of words never practiced by
the child, either as totals or in their syllables separately, _do_
occur,—that children do respond by repeating a word in cases where full
knowledge of all their previous habits would give no reason to expect
them to make such a connection. To this the only retort is that such
observations should be based on a very delicate and very elaborate record
of a child’s linguistic history, and that until they are so made, it is
wise to withhold acceptance.
The second objection is that the rapid acquisition of a vocabulary
such as occurs in the second and third year is too great a task to be
accomplished by the laws of exercise and effect alone. This objection
is based on an overestimation of the variety of sounds which children
of the ages in question make. For example, a child who says 250 words,
including say 400 syllables, comprising say 300 syllables which, when
properly pronounced, are distinguishable, may actually use less than 50
distinguishable syllables. _Ba_, may stand for the first syllable of
father, water, barn, park and the like. _Ki_ may stand for cry, climb,
and even carry. For a child to say a word commonly means that he makes
a sound which his intimate companions can recognize as his version of
that word. A child who can produce something like each one of a thousand
words upon hearing them, may do so from actual control over less than
a hundred syllables. If we suppose him to have acquired the habits,
first, of saying _something_ in such a case, second, of responding to a
certain hundred sounds when perceived or remembered by making, in each
case, a similar sound, and, third, of responding to any other sound when
perceived or remembered, by making that sound of his own repertory which
is most like it,[42] we can account for a thousand ‘imitations,’ and
still not have made a large demand upon childish powers of learning.
No one should pretend to have disproved direct imitation in the case of
learning to talk until he has subjected all these and other matters to
crucial experiments. But the burden of proof does seem to belong upon
those who deny the adequacy of the laws of exercise and effect. In so far
as the choice is between accepting or rejecting a general law that, other
things being equal, the perception of a response in another produces that
response, we surely must reject it. Some of the cases of imitation may be
unexplained by the laws of exercise and effect. But for others no law of
imitation is required. And of what should happen by such a law not over a
trivial fraction at most does happen.
_The idea of a response is in and of itself unable to produce
that response._
The early students of behavior, considering human behavior and
emphasizing behavior that was thought about and purposive, agreed that
the sure way to connect a response with a situation was to choose, or
will, or consent to, that response. Later students still agreed that
to think about the response in some way, to have an image of it or of
the sensations caused in you by previous performances of it, was a
strong provocative to it. To get a response, get some sort of conscious
representative of it, has been an acceptable maxim. Medicine, education
and even advertising have based their practice upon the theory that ideas
tended to issue in the particular sort of acts that they were ideas of.
The laws of exercise and effect, on the contrary, if they are the sole
laws of modifiability, insist that the thought of an act will produce
that act only if the act has been connected with that thought (and
without resulting discomfort) in the animal’s past.
It seems plausible that there should be a peculiar bond between the
thought of a response and the response. The plausibility is due to two
reasons, one of which is sound but inadequate, the other being, in my
opinion, entirely unsound. The first reason is that, as a mere matter
of fact, the thought of a response does so often produce it. The second
is that an idea of a response seems a natural and sufficient cause for
it to appear. The first reason is inadequate to justify any law of the
production of a response by its image or other representative, since
evidence can be found to show that when a response is produced by an
idea of it, it has been already bound to that idea by repetition or
satisfaction. The second reason is unsound because, even if responses are
brought to pass occasionally by their images, that is surely an extremely
rare and unnatural method.
It is certain that in at least nine cases out of ten a response is
produced, not by an image or other representation of it, but by a
situation nowise like it or any of its accessories. Hunger and the
perception of edible objects, far outweigh ideas of grasping, biting and
swallowing, as causes of the eating done in the world. Objects sensed,
not images of eye-movements, cause a similar overwhelming majority of
the eye’s responses. We walk, reach and grasp on most occasions, not
because of anticipatory images of how it will feel to do so or verbal
descriptions to ourselves of what we are to do, but because we are
stimulated by the perception of some object.
It is also certain that the idea of a response may be impotent to
produce it. I cannot produce a sneeze by thinking of sneezing. A child
may have, in the case of some simple bodily act, which he has done in
response to certain situations thousands of times, as adequate ideas of
it as are possessed by others, and yet be utterly unable to make himself
do it; many adults show this same phenomenon, for instance, in the case
of swallowing a pill. And, of course, one can have ideas of running a
mile in two minutes, jumping a fence eight feet high, or drawing a line
exactly equal to a hundred millimeter line, just as easily as of running
the mile in ten minutes, or jumping four feet.
It is further certain that the thought of doing one thing very often
results in the man’s doing something quite different. The thought of
moving the eyes smoothly without stops along a line of print has occurred
to many people, who nevertheless actually did as a result move the eyes
in a series of jumps with long stops.
It is further certain that in many cases where an animal does connect a
given response with the image or thought of that response, the connection
has been built up by the laws of exercise and effect. Such cases as
appropriate responses to, ‘I will go to bed,’ ‘I will get up,’ ‘I will
eat,’ ‘I will write a letter,’ ‘I will read,’ or to the corresponding
commands, requests or suggestions, are observably built up by training.
The appropriate response follows the idea only if it has, by repetition
or reward, been connected with it or something like it. If the only
requirement in moral education were to have the idea of the right act
at the right time, the lives of teachers and parents would be greatly
alleviated. But the decision to get up, or the idea of getting up or of
being up, is futile until the child has connected therewith the actual
act of getting up.
The defender of the direct potency of conscious representatives of a
response to produce it may be tempted to complain at this point that what
the laws of exercise and effect do is to reduce the strength of competing
ideas, and leave the idea, say of getting up, free to exercise its direct
potency. The complaint shows a weak sense for fact. The ordinary child is
not a Hamlet, nor is he beguiled by the imagined delights of staying in
bed, nor repelled by the image of getting up out of it. On the contrary,
he may be entirely willing to _think of_ getting up. It is the actual
delights that hold him, the actual discomforts that check him, and the
only way to be sure that he will get up is so to arrange matters that it
is more satisfactory to him to get up than not to when the situation,
whatever it be, that is to suggest that response, makes its appearance.
The experience of every schoolroom shows that it is not enough to get the
idea of an act. The act must have gone with that idea or be now put with
it. The bond must be created. Responses to the suggestions of language,
whether addressed to us by others or by ourselves in inner speech, in
a very large majority of cases owe their bonds to the laws of exercise
and effect. We learn to do what we are told, or what we tell ourselves,
by doing _something_ and rejecting or retaining what we do by virtue
of its effects. So also in the case of a majority of responses to the
suggestions of other than verbal imagery.
The idea of a response, like the perception of a response by another,
acts often as a guide to response _ex post facto_ by deciding what shall
be satisfying. Where superficial inspection leaves the impression that
the idea creates the act, a little care often shows it to have only
selected from the acts produced by instinct and habit. For example, let
the reader think of some act never performed hitherto, such as putting
his left middle finger upon the upper right hand corner of this page,
and make the movement. It may seem at first sight that having the idea
entirely unopposed was the sufficient cause of the act. But careful
experiment, including, for instance, the closure of the eyes and
anesthesia of the fingers will reveal that the original propulsion of the
idea is not to just that act, but to many possibilities, and that its
chief potency lies in the fact that not to get the finger to that point
is annoying, and that consequently the organism is at peace only when the
act is done.
So far it has been shown that: The majority of responses are not produced
by ideas of them. The idea of a response may be impotent to produce it.
The idea of one act may produce a different, even an opposite act. When
an idea seems to produce a response in and of itself, it may really act
by determining the satisfyingness of responses otherwise made. These
facts are sufficient to destroy the pretensions of any general law that
the image of an act will, other things being equal, produce it. But the
possibility that such an image may occasionally exercise this peculiar
potency remains.
I despair of convincing the reader that it does not. Man is the
only animal possessing a large fund of ideas of acts, and man’s
connection-system is so complex and his ideas of acts are so intricately
bound to situations that have by use and effect produced those acts,
that the proof of this negative is a practical impossibility. But it is
possible to show that even the most favored cases for the production of a
response by securing an ideal representation of it may be explainable by
use and effect alone.
The extreme apparent potency of ideas representing acts to produce them
regardless of bonds of use or effect is, of course, witnessed in the
phenomena of suggestion in hypnosis and allied states. To try to reduce
these phenomena to consequences of the laws of habit may seem fanatical.
Here, it will be said, are the crucial cases where the idea of an act, if
freed from all effects of opposing ideas, does inevitably produce the act
so far as it is a possibility for the animal’s action-system.
That is precisely what I cannot find proof of.
Efficient suggestions to hypnotized subjects, on the contrary, are often
ambiguous in the sense that they seem as likely to arouse a situation
_to which the act has been bound by the law of habit_ as to arouse an
idea of the act. Often they are far better suited to the former purpose.
Direct commands—Walk, Dance, Get up, Sit down—obviously will operate by
the law of habit provided the situations connected with disobedience are
excluded. This is also the case with such indirect suggestions as ‘This
is a knife (stick).’ ‘This is your sword (broom).’ ‘Have a cigar (a pen).’
The release of a suggestion from inhibitions may as well be the release
from _ideas connected as antecedents with_ not performing the act as
the release from _ideas of_ not performing it. It is a question of fact
whether, to get an act done by the subject, one must arouse in him an
idea to which or to a part of which or to something like which the act
has been bound by use or effect, or may arouse simply an idea of the act.
Finally, if an idea has a tendency to connect with a certain response,
over and above the bonds due to exercise and effect, it should _always_
manifest that tendency. If the connection is not made, it must be due to
the action of some contrary force. It is less my duty to show that the
laws of habit can account for hypnotic suggestibility, obsessions, and
the like, than it is my opponents’ duty to explain why a man can spend a
half day in hospitably welcoming a hundred ideas of acts and yet perform
no one of them, save those in the case of which he has learned to do the
thing when he thinks of doing it. Again, how can the mere addition of
the idea of a future date to the idea of an act so utterly deprive it of
present potency.
In view of all these facts it seems probable that ideas of responses act
in connection just as do any other situations, and that the phenomena of
suggestion and ideo-motor action really mean that any idea will, except
for competing ideas, produce the response, not that _is like it_, but
that _has gone with it_, or with some idea like it.
_Rational connections are, in their causation, like any others,
the difference being in what is connected._
It remains to ask whether situation and response are bound together in
the case of reasoning by any other forces than the forces of repetition,
energy and satisfaction? Do the laws of inferential thinking transcend
the laws of exercise and effect? Or does the mind, even in these novel
and constructive responses, do only what it is forced to do by original
nature or has done without discomfort?
To defend the second alternative involves the reduction of the processes
of abstraction, association by similarity and selective thinking to mere
secondary consequences of the laws of exercise and effect. This I shall
try to do.
The gist of the fact of abstraction is that response may be made to some
elements or aspects of a situation which have never been experienced
in isolation, and may be made to the element in question regardless of
the gross total situation in which it inheres. A baby thus learns to
respond to its mother’s face regardless of what total visual field it is
a part of. A child thus learns to respond by picking out any red object,
regardless of whether the redness be in an apple, a block, a pencil, a
ribbon or a ball. A student thus learns to respond to any plane surface
inclosed by three straight lines regardless of its size, shape, color or
other than geometrical meaning.
What happens in such cases is that the response, by being connected with
many situations alike in the presence of the element in question and
different in other respects, is bound firmly to that element and loosely
to each of its concomitants. Conversely any element is bound firmly to
any one response that is made to all situations containing it and very,
very loosely to each of those responses that are made to only a few of
the situations containing it. The element of triangularity, for example,
is bound firmly to the response of saying or thinking ‘triangle’ but only
very loosely to the response of saying or thinking white, red, blue,
large, small, iron, steel, wood, paper and the like. A situation thus
acquires bonds not only with some response to it as a gross total, but
also with responses to each of its elements that has appeared in any
other gross totals.
Appropriate response to an element regardless of its concomitants is a
necessary consequence of the laws of exercise and effect if an animal
learns to make that response to the gross total situations that contain
the element and not to make it to those that do not. Such prepotent
determination of the response by one or another element of the situation
is no transcendental mystery, but, given the circumstances, a general
rule of all learning. The dog who responds appropriately to ‘beg’ no
matter when, where, or by whom spoken, manifests the same laws of
behavior. There is no difficulty in understanding how each element of a
situation may come to tend to produce a response peculiar to it as well
as to play its part in determining the response to the situation as a
total. There may be some difficulty in understanding how each element
of a situation comes to be _felt_ whereas before only the gross total
was felt. The change in consciousness from the ‘big, blooming, buzzing
confusion’ to an aggregate of well-defined percepts and images, which
accompanies the change in behavior from response to totals to response to
parts or elements, may be mysterious. With the change in consciousness,
however, we are not now concerned. The _behavior_ of man and other
animals toward the abstract elements of color, size, number, form, time
or value is explained by the laws of instinct, exercise and effect.
When the perception or thought of a fact arouses the thought of some
other fact identical in part with the former fact, we have so-called
association by similarity. An element of the neurone-action is prepotent
in determining the succeeding neurone-action. The particular way in which
it determines it is by itself continuing and making connection with other
associates. These it possesses by virtue of the law of exercise and
effect.
* * * * *
The changes in behavior classified under intellect and morality seem
then to be all explainable by the two laws of exercise and effect. The
facts of imitation really refer to certain specific original connections
or to the efficiency of a model in determining what shall satisfy or
to the provision of certain instructive situations in the form of the
behavior of other animals. The facts variously referred to as suggestion,
ideo-motor action or the motor power of ideas, really refer to the fact,
common in the human animal only, that to those ideas that represent acts
in thought the acts are often bound as responses. The bonds are due to
the primary laws of effect and exercise. The facts of reasoning really
refer to the fact of prepotency of one or another element in a situation
in determining the response.
The reduction of all learning to making and rewarding or avoiding and
punishing connections between situation and response allows changes in
intellect and character to be explained by changes in the neurones that
are known either to be or to be possible. I have elsewhere sketched one
such possible neural mechanism for the law of effect.[43]
On the contrary, imitation, suggestion and reasoning, as commonly
described, put an intolerable burden upon the neurones. To any one who
has tried to imagine a possible action in the neurones to parallel the
traditional power of the mere perception of an act in another or of the
mere representation of an act as done by oneself to produce that act,
this is a great merit. For the only adequate psychological parallel of
traditional imitation and suggestion would be the original existence or
the gratuitous formation of a connection between (1) each neurone-action
corresponding to a percept of an act done by another or to the idea of
an act done by oneself and (2) the neurone-action arousing that act. It
is incredible that the neurone-action corresponding to the perception of
a response in another, or to the idea of a response in oneself, or to
the first term in an association by similarity, should have, in and of
itself, a special power to determine that the next neurone-action should
be that paralleling the response in question. And there is no possible
physiological parallel of a power to jump from premise to conclusion for
no other reason than the ideal fitness of the sequence.
SIMPLIFICATIONS OF THE LAWS OF EXERCISE AND EFFECT
There has been one notable attempt to explain the facts of learning by
an even simpler theory than that represented in the laws of exercise
and effect. Jennings has formulated as an adequate account of learning
the law that: “When a certain physiological state has been resolved,
through the continued action of an external agent, or otherwise, into
a second physiological state, this resolution becomes easier, so that
in course of time it takes place quickly and spontaneously” (‘Behavior
of the Lower Organisms,’ p. 289). “The law may be expressed briefly as
follows:—_The resolution of one physiological state into another becomes
easier and more rapid after it has taken place a number of times._ Hence
the behavior primarily characteristic for the second state comes to
follow immediately upon the first state. The operations of this law are,
of course, seen on a vast scale in higher organisms in the phenomena
which we commonly call memory, association, habit formation and learning”
(_ibid._, p. 291). This law may be expressed conveniently as a tendency
of a series of states
A -> B -> C -> D
to become
A -> D
or
A -> B¹ -> C¹ -> D
B¹ and C¹ being states B and C passed rapidly and in a modified way so
that they do not result in a reaction but are resolved directly into D.
If Professor Jennings had applied to this law the same rigorous analysis
which he has so successfully employed elsewhere, he would have found that
it could be potent to cause learning only if supplemented by the law of
effect and then only for a fraction of learning.
For, the situations being the same, the state A cannot produce, at one
time, now B and, at another time, abbreviated, rudimentary B¹ instead of
B. If A with S produces B once, it must always. If D or a rudimentary B¹
is produced, there must be something other than A; A must itself have
changed. Something must have been added to or subtracted from it. In
Professor Jennings’ own words, “Since the external conditions have not
changed, the animal itself must have changed” (_ibid._, p. 286). And in
adaptive learning something related to the results of the S A connection
must have changed it.
The series A—B—C—D does not become the series A—D or A—B¹—C¹—D by magic.
If B and C are weakened and D is strengthened as sequents of A in
response to S, it is because something other than repetition acts upon
them. Repetition alone could not blow hot for D and cold for B.
Moreover, as a mere matter of fact, “the resolution of one physiological
state into another” through intermediate states does not with enough
repetition “become easier so that in course of time it takes place
quickly and spontaneously.”
Paramecium does not change its response to, say, an obstacle in the
water, from swimming backward, turning to one side and swimming forward
by abbreviating and eventually omitting the turn and the backward
movement. The schoolboy does not tend to count 1, 2, 10 or to say a, b,
z, or give ablative plurals after nominative singulars.
Repetition of a series of physiological states in and of itself on the
contrary makes an animal increasingly _more_ likely to _maintain_ the
series _in toto_. It is hard to give the first and then the last word of
an oft repeated passage like Hamlet’s soliloquy or the Lord’s Prayer, or
to make readily the first and then the last movement of writing a name or
address. Repetition never eliminates absolutely and eliminates relatively
the _less_ often or _less_ emphatically connected.
Even if supplemented by the law of effect, so that some force is at hand
to change the effect of S upon the animal to A D instead of the original
A B C D, the law of the resolution of physiological states would be
relevant to only a fraction of learning. For example, let a cat or dog be
given an ordinary discrimination experiment, but so modified that whether
the animal responds by the ‘right’ or the ‘wrong’ act _he is removed
immediately after the reward or punishment_. That is, the event is either
S R1 or S R2, never S R1 R2. Let the experiment be repeated at intervals
so long that the physiological state, St. R1, or St. R2, leading to the
response R1 or R2 in the last trial, has ceased before the next. The
animal will come to respond to S by R2 only, though R2 has never been
reached by the ‘resolution’ of S R1 R2.
Cats in jumping for birds or mice, men in playing billiards, tennis or
golf, and many other animals in many other kinds of behavior, often learn
as the dog must in this experiment. The situation on different occasions
is followed by different responses, but by only one per occasion.
Professor Jennings was misled by treating as general the special case
where the situation itself includes a condition of discomfort terminable
only by a ‘successful’ response or by the animal’s exhaustion or death.
Assuming as typical this same limited case of response to an annoying
situation, so that success consists simply in replacing the situation
by another, Stevenson Smith reduces the learning-process to the law of
exercise alone. He argues that,—
“For instance, let an organism at birth be capable of giving N reactions
(a, b, c, ... N) to a definite stimulus S and let only one of these
reactions be appropriate. If only one reaction can be given at a time
and if the one given is determined by the state of the organism at the
time S is received, there is one chance in N that it is the appropriate
reaction. When the appropriate reaction is finally given, the other
reactions are not called into play, S may cease to act, but until the
appropriate reaction is given let the organism be such that it runs
through the gamut of the others until the appropriate reaction is brought
about. As there are N possible reactions, the chances are that the
appropriate reaction will be given before all N are performed. At the
next appearance of the stimulus, which we may call S₂, those reactions
which were in the last case performed, are, through habit, more likely to
be again brought about than those which were not performed. Let _u_ stand
for the unperformed reactions. Then we have N - _u_ probable reactions
to S₂. Habit rendering the previously most performed reactions the most
probable throughout we should expect to find the appropriate reaction in
response to
S₁ contained in N.
S₂ contained in N - _u₁_.
S₃ contained in N - _u₁_ - _u₂_.
...
S_ₙ_ contained in N - _nu_, which approaches _one_ as a limit.
Thus the appropriate reaction would be fixed through the laws of chance
and habit. This law of habit is that when any action is performed
a number of times under certain conditions, it becomes under those
conditions more and more easily performed” (_Journal of Comparative
Neurology and Psychology_, 1908, Vol. XVIII, pp. 503-504).
This hypothesis is, like Professor Jennings’, adequate to account for
only the one special case, and is adequate to account for that only
upon a further limitation of the number of times that the animal may
repeat any one of his varied responses to the situation before he has
gone through them all once, or reached the one that puts an end to the
situation.
The second limitation may be illustrated in the simple hypothetical case
of three responses, 1, 2 and 3, of which No. 2 is successful. Suppose the
animal always to go through his repertory with _no_ repetitions until he
reaches 2 and so closes the series.
Only the following can happen:—
1 2
1 3 2
2
2
3 1 2
3 2
and, in the long run, 2 will happen twice as often as 1 or 3 happens.
Suppose the animal to repeat each response of his repertory six times
before changing to another, the remaining conditions being as above. Then
only the following can happen:—
1 1 1 1 1 1 2
1 1 1 1 1 1 3 3 3 3 3 3 2
2
2
3 3 3 3 3 3 1 1 1 1 1 1 2
3 3 3 3 3 3 2,
and in the long run 2 will happen one third as often as 1 or 3 and,
though always successful, must, by Smith’s theory, appear later and
later, so that if the animal meets the situation often enough, he will
eventually fail utterly in it!
Animals do, as a matter of fact, commonly repeat responses many times
before changing them,[44] so that if only the law of exercise operated,
learning would not be adaptive. It is the _effect_ of 2 that gives it the
advantage over 1 and 3. Of two responses to the same annoying situation,
one continuing and the other relieving it, an animal could never learn to
adopt the latter as a result of the law of exercise alone, if the former
was, originally, twice as likely to occur. 1 1 2 would occur as often
as 2 and exercise would be equal for both. The convincing cases are, of
course, those where learning equals the strengthening to supremacy of an
originally very weak connection and the weakening of originally strong
bonds. An animal’s original nature may lead it to behave as shown below:—
1 1 1 3 1 1 4 1 1 2
1 1 1 1 3 1 1 1 3 1 1 4 2
4 1 1 3 3 1 1 4 4 1 1 1 1 1 2, etc.,
and yet the animal’s eventual behavior may be to react to the situation
always by 2. The law of effect is primary, irreducible to the law of
exercise.
THE EVOLUTION OF BEHAVIOR
The acceptance of the laws of exercise and effect as adequate accounts of
learning would make notable differences in the treatment of all problems
that concern learning. I shall take, to illustrate this, the problem of
the development of intellect and character in the animal series, the
phylogenesis of intellectual and moral behavior.
The difficulties in the way of understanding the evolution of
intellectual and moral behavior have been that neither what had been
evolved nor that from which it had been evolved was understood.
The behavior of the higher animals, especially man, was thought to be
a product of impulses and ideas which got into the mind in various
ways and had power to arouse certain acts and other ideas more or
less mysteriously, in the manner described by the laws of ideo-motor
action, attention, association by contiguity, association by similarity,
suggestion, imitation, dynamo-genesis and the like, with possibly a
surplus of acts and ideas due to ‘free will.’ The mind was treated as
a crucible in which a multifarious solution of ideas, impulses and
automatisms boiled away, giving off, as a consequence of a subtle
chemistry, an abundance of thoughts and movements. Human behavior was
rarely viewed from without as a series of responses bound in various
ways to a series of situations. The student of animal behavior passed as
quickly as might be from such mere externals to the inner life of the
creature, making it his chief interest to decide whether it had percepts,
memories, concepts, abstractions, ideas of right and wrong, choices,
a self, a conscience, a sense of beauty. The facts in intellect and
character that are due to learning, that are not the inherited property
of the species and that consequently are beyond the scope of evolution
in the race, were not separated off from the facts of original nature.
The comparative psychologist misspent his energy on such problems as the
phylogenesis of the idea of self, moral judgments, or the sentiment of
filial affection.
At the other extreme, the behavior of the protozoa was either
contemplated in the light of futile analogies,—for instance, between
discriminative reactions and conscious choice, and between inherited
instincts and memory,—or studied crudely in its results without
observation of what the animals really did. The protozoa were regarded
either as potential ‘conscious selves’ or as drifting lumps turned hither
and thither by the direct effects of light, heat, gravity and chemical
forces upon their tissues.
The evolution of the intellectual and moral nature which a higher animal
really possesses from the sort of a nature which the real activities of
the protozoa manifest, is far less difficult to explain.
In so far as the higher animal is a collection of original tendencies
to respond to physical events without and within the body, subject to
modification by the laws of exercise and effect and by these alone,
and in so far as the protozoan is already possessed of a well-defined
repertory of responses connected with physical events without and within
the body in substantially the manner of the higher animal’s original
tendencies, the problems of the evolution of behavior are definite and in
the way of solution.
The previous sections gave reason for the belief that the higher animals,
including man, manifest no behavior beyond expectation from the laws
of instinct, exercise and effect. The human mind was seen to do no
more than connect in accord with original bonds, use and disuse, and
the satisfaction and discomfort resulting to the neurones. The work
of Jennings has shown that the protozoa already possess full-fledged
instincts, homologous with the instincts of man. They too may have
specialized receptors, an action-system with a well-defined repertory and
a connecting system or means of influencing the bonds between the stimuli
received and the motor reactions made. The difficulties of tracing the
possible development of a super-man from an infra-animal thus disappear.
There is, of course, an abundance of _bona fide_ difficulty in
discovering the unlearned behavior of each group of animals and in
tracing, throughout the animal series, changes in the physical events to
which animals are sensitive so that to each a different response may be
attached, changes in the movements of which animals are capable, and
changes in the bonds by which particular movements follow particular
physical events. To find when and how animals whose natures remained
nearly or quite unchanged by the satisfying and annoying effects of their
behavior, gave birth to animals that could learn, is perhaps a still
harder task. But these tasks concern problems that are intelligible
matters of fact. They do not require a student to get out of matter
something defined as beyond matter, or to get volition out of tropisms,
or to get ideas of space and time out of swimming and sleeping.
The evolution of the sensitivities and of the action-systems of animals
has already been subjected to matter-of-fact study by naturalists. The
evolution of the connection-system will soon be. Each reflex, instinct
or capacity, each bond between a given situation presented to a given
physiological state and a given response, has its ancestral tree.
Scratching at an irritated spot on the skin is older than arms. Following
an object that is moving slowly does not have to be explained separately,
as a ‘chance’ variation in dogs, sheep and babies. The mechanical trades
of man are related to the miscellaneous manipulations of the apes. Little
as we know of the connection-systems possessed by animals, we know enough
to be sure that a bond between situation and response has ancestors and
children as truly as does any bodily organ. Professor Whitman a decade
ago showed the possibility of phylogenetic investigation of instinctive
connections in a study which should be a stimulus and model for many
others. In place of any further general account of the study of the
phylogeny of the connection-system, I shall quote from his account of the
concrete phylogeny of the instinct of incubation.
“_b. The Incubation Instinct_
1. _Meaning to be Sought in Phyletic Roots._—It seems quite
natural to think of incubation merely as a means of providing
the heat needed for the development of the egg, and to assume
that the need was felt before the means was found to meet it.
Birds and eggs are thus presupposed, and as the birds could
not have foreseen the need, they could not have hit upon the
means except by accident. Then, what an infinite amount of
chancing must have followed before the first ‘cuddling’ became
a habit, and the habit a perfect instinct! We are driven to
such preposterous extremities as the result of taking a purely
casual feature to start with. Incubation supplies the needed
heat, but that is an incidental utility that has nothing to do
with the nature and origin of the instinct. It enables us to
see how natural selection has added some minor adjustments, but
explains nothing more. For the real meaning of the instinct we
must look to its phyletic roots.
If we go back to animals standing near the remote ancestors of
birds, to the amphibia and fishes, we find the same instinct
stripped of its later disguises. Here one or both parents
simply remain over or near the eggs and keep a watchful guard
against enemies. Sometimes the movements of the parent serve to
keep the eggs supplied with fresh water, but aëration is not
the purpose for which the instinct exists.
2. _Means Rest and Incidental Protection to Offspring._—The
instinct is a part of the reproductive cycle of activities,
and always holds the same relation in all forms that exhibit
it, whether high or low. It follows the production of eggs,
or young, and means primarily, as I believe, rest, with
incidental protection to offspring. That meaning is always
manifest, no less in worms, molluscs, crustacea, spiders and
insects, than in fishes, amphibia, reptiles and birds. The
instinct makes no distinction between eggs and young, and that
is true all along the line up to birds, which extend the same
blind instinct to one as to the other.
3. _Essential Elements of the Instinct._—Every essential
element in the instinct of incubation was present long
before the birds and eggs arrived. These elements are:
(1) the disposition to remain with or over the eggs; (2)
the disposition to resist and drive away enemies; and (3)
periodicity. The birds brought all these elements along in
their congenital equipment, and added a few minor adaptations,
such as cutting the period of incubation to the need of normal
development, and thus avoiding indefinite waste of time in case
of sterile or abortive eggs.
(1) _Disposition to Remain over the Eggs._—The disposition to
remain over the eggs is certainly very old, and is probably
bound up with the physiological necessity for rest after a
series of activities tending to exhaust the whole system. If
this suggestion seems far-fetched, when thinking of birds, it
will seem less so as we go back to simpler conditions, as we
find them among some of the lower invertebrate forms, which are
relatively very inactive and predisposed to remain quiet until
impelled by hunger to move. Here we find animals remaining
over their eggs, and thus shielding them from harm, from sheer
inability or indisposition to move. That is the case with
certain molluscs (_Crepidula_), the habits and development of
which have been recently studied by Professor Conklin. Here
full protection to offspring is afforded without any exertion
on the part of the parent, in a strictly passive way that
excludes even any instinctive care. In _Clepsine_ there is a
manifest unwillingness to leave the eggs, showing that the
disposition to remain over them is instinctive. If we start
with forms of similar sedentary mode of life, it is easy to see
that remaining over the eggs would be the most likely thing
to happen, even if no instinctive regard for them existed.
The protection afforded would, however, be quite sufficient
to insure the development of the instinct, natural selection
favoring those individuals which kept their position unchanged
long enough for the eggs to hatch.”[45]
Professor Whitman proceeds to study the ‘Disposition to Resist
Enemies’ and the ‘Periodicity’ in the same genetic way.
The most important of all original abilities is the ability to learn. It,
like other capacities, has evolved. The animal series shows a development
from animals whose connection-system suffers little or no permanent
modification by experience to animals whose connections are in large
measure created by use and disuse, satisfaction and discomfort.
Some of this development can be explained without recourse to differences
in mere power to learn, by the fact that the latter animals are given
greater stimuli to or rewards for learning. But part of it is due to
differences in sheer ability to learn, that is, in the power of equally
satisfying conditions to strengthen or of equally annoying conditions to
weaken bonds in the animals’ connection-systems. This may be seen from
the following simple and partial case:—
Call 1 and 2 two animals.
Call C₁ and C₂ the internal conditions of the two animals except for
their connection-systems, each being the average condition of the animal
in question.
Call S₁ and S₂ two external states of affairs, each being near the
indifference point for the animal in question,—that is, being one which
the animal does little to either avoid or secure.
Call G₁ and G₂ two responses which result in O₁ and O₂ the _optima_ or
most satisfying state of affairs for 1 and 2.
Call I₁ and I₂ two responses which result in the continuation of S₁ and
S₂.
The only responses possible for 1 are G₁ and I₁.
The only responses possible for 2 are G₂ and I₂.
Animal 1 upon the recurrence of S₁ and C₁ is little or no more likely to
respond by G₁ than he was before.
Animal 2 upon the recurrence of S₂ and C₂ is far more likely to respond
by G₂ than he was before.
The fact thus outlined might conceivably be due to an intrinsic
inequality between O₁ and O₂, the power of equally satisfying _optima_ to
influence, their antecedents being identical. This is not the case in the
evolution of learning, however. For even if, instead of O₂, we had only
a moderately satisfying state of affairs, such as the company of other
chicks to (2) a 15-day-old chick, while O₁ was the optimum of darkness,
dampness, coolness, etc., for (1) an earthworm, 2 would learn far, far
more rapidly than 1.
The fact is due, of course, to the unequal power of equally satisfying
conditions to influence their antecedents. The same argument holds good
for the influence of discomfort.
The ability to learn,—that is, the possession of a connection-system
subject to the laws of exercise and effect,—has been found in animals as
‘low’ as the starfish and perhaps in the protozoa. It is hard to tell
whether the changed responses observed in Stentor by Jennings and in
Paramecium by Stevenson Smith are easily forgotten learnings or long
retained excitabilities. Sooner or later clear learning appears, and
then, from crabs to fish and turtle, from these to various birds and
mammals, from these to monkeys, and from these to man, a fairly certain
increase in sheer ability to learn, in the potency of a supposedly
constant degree of satisfyingness or annoyingness to influence the
connection preceding it, can be assumed. We cannot, of course, define
just what we mean by equal satisfyingness to a mouse and a man, but the
argument is substantially the same as that whereby we assume that the
gifted boy has more sheer ability to learn than the idiot, so that if
the two made the same response to the same situation and were equally
satisfied thereby, the former would form the habit more firmly.
We may, therefore, expect that when knowledge of the structure and
behavior of the neurones comprising the connection-systems of animals (or
of the neurones’ predecessors in this function) progresses far enough
to inform us of just what happens when a connection is made stronger or
weaker and of just what effects satisfying and annoying states of affairs
exert upon the connection-system (and in particular upon the connections
most recently in activity) the ability to learn will show as true an
evolution as the ability to sneeze, oppose the thumb, or clasp an object
touched by the hand.
If my analysis is true, the evolution of behavior is a rather simple
matter. Formally the crab, fish, turtle, dog, cat, monkey and baby have
very similar intellects and characters. All are systems of connections
subject to change by the law of exercise and effect. The differences
are: first, in the concrete particular connections, in _what_ stimulates
the animal to response, _what_ responses it makes, _which_ stimulus
connects with _which_ response, and second, in the degree of ability to
learn—in the amount of influence of a given degree of satisfyingness or
annoyingness upon the connection that produced it.
The peculiarly human features of intellect and character, responses to
elements and symbols, are the results of: first, a receiving system that
is easily stimulated by the external world bit by bit (as by focalized
vision and touch with the moving hand) as well as in totals composed
of various aggregates of these bits; second, of an action-system of
great versatility (as in facial expression, articulation, and the
hands’ movements); and third, of a connection-system that includes the
connections roughly denoted by babbling, manipulation, curiosity, and
satisfaction at activity, bodily or mental, for its own sake; that is
capable of working in great detail, singling out elements of situations
and parts of responses; and that allows satisfying and annoying states of
affairs to exert great influence on their antecedent connections. Because
he learns fast and learns much, in the animal way, man seems to learn by
intuitions of his own.