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D.—ZOOLOGY 95 
and by the connections already existing in the nervous system or built 
up during the formation of conditioned reflexes. 
There is no time, and no need, for me to criticise this view in detail. 
Actually the strict theory of connectionism is rapidly breaking down in 
face of the facts established by the brilliant work of Lashley on the one 
hand and the Gestalt psychologists on the other. I will merely point 
out, first, that this analytical and physiological view is a pure hypothesis, 
derivable from the Cartesian metaphysics, and second, that it does not 
harmonise well with the simplest facts of observation. 
Nothing is more striking than the apparent spontaneity of animal 
actions, their independence of the immediately present external stimulus. 
When an animal is hungry it goes and looks for food ; when a hunting 
wasp requires provisions for her future offspring she actively seeks high 
and low for the proper caterpillar or spider that she needs ; when a bird 
is building her nest she looks everywhere for the grass or feathers or moss 
she requires. As Koffka well expresses it: ‘ While reflexes are typically 
“passive ’’ modes of behaviour, which depend upon the fact that some 
stimulation has taken place, instinctive behaviour is, by contrast, signifi- 
cantly “ active’ in its search for stimuli. The bird seeks the material 
for its nest, and the predatory animal stalks its game. In other words, 
the stimulating environment is not a sufficient cause for these activities. 
Every movement requires forces which produce it; but the forces that 
produce instinctive activities are not in the stimulus-situation—they are 
within the organism itself. The needs of the organism are the ultimate 
causes of its action; and when these needs have been satisfied, the 
action comes to an end.’ § 
A very great part of the behaviour of animals is, quite simply, response 
to needs (or deviations from normal), and not to direct external stimula- 
tion. When a starfish is turned on its back it tries in various ways to 
right itself, or, more accurately, to re-establish contact with a solid surface. 
Careful study of the action by Fraenkel and others has clearly established 
that the real ‘ stimulus ’ to the action, if one may use the word stimulus 
at all, is not something positive, but simply the lack of contact between 
the tube-feet and some solid object, the need to re-establish a normal 
functional relation to the substratum. No doubt in all cases of action 
‘directed towards satisfying a need introception comes into the story, 
but the broad fact remains that it is lack of normality, or the absence of 
some condition necessary for maintenance or development or repro- 
duction, that sets much of behaviour going. 
I do not, however, wish to over-emphasise the autonomy of behaviour, 
its independence of external stimulation. It is certainly true that 
behaviour is to a considerable extent influenced by events in the animal’s 
€nvironment which it perceives and to which it responds. Thus all 
animals react to danger or to signs of danger by appropriate behaviour. 
Some like the rabbit bolt for their burrows ; others like the squirrel take 
refuge up a tree ; the antelope trusts to its fleetness, and most birds to 
8 K. Koffka, The Growth of the Mind, 2nd edit., London, 1928, p. 103. 
