A sensation, an emotion, an idea, etc., may leave a more or less
permanent memory which can, perhaps, be recalled years later. Where was
this memory in the meanwhile? The usual explanation is that a sort of
groove or trace is cut into certain brain cells,--just as the recording
needle cuts a groove in the phonograph record, recording at the same
time the _music_; and that the act of recalling a memory is analogous
to reproducing the music, by means of a suitable device upon the
phonograph. The brain is, on this view, “the physical basis of memory.”
One difficulty which at once arises, however, is that, inasmuch as all
parts of the body are constantly being made-over, and replaced by new
parts, these brain-cells must also be replaced (within a few weeks,
months or years) and the record would vanish with them. The usual reply
to this is that the newly laid-down brain-cell in some way “inherits”
the memory from the old one, and hence somehow continues to store its
psycho-physical memories, which are again passed-on when this cell is
replaced, and so on forever.
Needless to say, such an interpretation of the facts strains our
credulity. None other, however, has ever been forthcoming. But the
inherent difficulty of the case has led some philosophers--notably
Bergson--to defend the idea that the brain is merely a mechanism for
_reproducing_ memories, and that memory itself resides within some
spiritual storehouse, where it remains until recalled. The legitimacy
of such a view, of course, rests upon the possible proof of such a
super-physical world as that postulated.
Memory depends upon a variety of factors. A healthy brain is essential
to a good memory; good blood, bathing healthy nerve-cells being here
essential. Memory also depends upon (1) interest, and (2) association.
We remember a thing which interests us; it makes an “impression” upon
us. Also, if we associate a thing with other things, it helps us
to remember it. An isolated fact is hard to remember; but if it is
associated with a number of other things which we know, or which also
interest us, it is more liable to be recalled. Any one of these things
may then recall the other event, by association, and hence the given
memory is more readily accessible.
Memory is first of all recorded, then stored, then recalled, and
finally recognized or “placed,” after it is recalled. Some authors
say that memory consists in three stages, others in as many as five
(Hyslop). This is merely a question of the sub-division of the process
involved.
It has been contended that there is no such thing as a “good” or a
“bad” memory; it all depends upon the factors above mentioned. Various
artificial schemes have been devised to improve and perfect the memory;
and there is no doubt that it is a faculty which can be greatly
improved by constant practice. In a sense, everything is remembered,
but it is not vivid enough to be recalled. Such hidden memories can
often be revived by means of hypnotism, etc. In certain abnormal
conditions, the memory seems to be keenly stimulated, and events, long
forgotten, are recalled, which had long before been forgotten by the
conscious mind. Many apparently “super-normal” phenomena have been
explained in this manner.