J.—PSYCHOLOGY. 1938 
It would appear, then, that the higher processes of learning, of 
comparison, and indeed of all that, underlies higher intelligent activity, 
have a generalised localisation—comparable, perhaps, to the diffusion of 
epicritic sensibility over the skin as contrasted with the more primitive, 
ungraded, spot systems of protopathic cutaneous sensibility, which in 
turn may perhaps be compared with the narrow so-called localisation of 
; visual, auditory and other ‘ sensory’ and low-grade areas in the cortex. 
_ But even where it exists, cortical localisation is only relatively definite. 
The boundaries of a given ‘ motor area’ in the cerebral cortex fluctuate 
widely in different individuals; they vary also in the same individual 
according to the direction of exploration, previous exploration and other 
factors; and, as we have already noted, other areas may successfully 
assume the function of that area when it is destroyed. A certain degree 
of ‘ equipotentiality ’ exists throughout the brain, although some cerebral 
regions appear normally to have fairly definite, circumscribed, lower-level 
functions. 
We are, in fact, neither warranted in supposing that there are definite 
‘seats or centres of sensation or emotion; nor justified in supposing that 
our manifold percepts, images or ideas each have their seat in different 
narrowly localised centres of the brain. And a similar truth holds for the 
association (or integration) of such experiences. . We can mentally picture 
an integration of two ‘ patterns’ of conscious activity occurring when two 
experiences a and b follow one another repeatedly, so that when a is later 
given, b (or rather the whole a—b) recurs. But neurologically we can form 
no simple corresponding picture of two collections of nerve cells being 
associated together. We have no evidence. to support such cerebral 
localisation of association areas; indeed such experimental evidence as 
we have is against it. 
Even if there were no evidence pointing in one direction or the other, 
how could such localisation of memories and habits possibly occur ? 
Consider the babe that is learning to associate its mother with the satis- 
faction of its hourly wants. Its mother is never twice the same—now in 
one dress or facial expression, now in another; and the visual image of 
the mother received by the retina is never twice the same, e.g. sometimes 
_ the mother is very near, sometimes further off ; sometimes the image falls 
on one part of the retina, sometimes on another. How can we imagine, 
then, any definite collection of retinal or cortical nerve cells responsible 
for developing the image of ‘ mother’? What develops is surely rather 
“a “meaning ’—a generalisation of images, ‘ standing for’ something, i.e. 
_ for the assuaging of certain needs, for the execution of a wide range of 
adjustments of the infant. 
Relationships and meanings are therefore the all-important mental 
acquirements. The acquisition of such relationships is shown, for example, 
ter B, the brighter of two alternative compartments, A and B, in order 
_ to reach its food. When later, in place of A and B, B and C are substi- 
tuted, C being now brighter than B, does the animal go to B to which 
_ it had previously been trained to go? Generally, no. It enters the C 
compartment. That is to say, it has learnt to enter not a particular 
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