Instinctive Behaviour 431 
experience. To the development of this experience each instinctive 
act contributes, The nature and manner of organisation of this 
primary tissue of experience are dependent on inherited biological 
aptitudes; but they are from the outset onwards subject to secondary 
development dependent on acquired aptitudes. Biological values are 
supplemented by psychological values in terms of satisfaction or the 
reverse. 
In our study of instinct we have to select some particular phase 
of animal behaviour and isolate it so far as is possible from the life 
of which it is a part. But the animal is a going concern, restlessly 
active in many ways. Many instinctive performances, as Darwin 
pointed out’, are serial in their nature. But the whole of active life 
is a serial and coordinated business. The particular instinctive 
performance is only an episode in a life-history, and every mode of 
behaviour is more or less closely correlated with other modes. This 
coordination of behaviour is accompanied by a correlation of the 
modes of primary experience. We may classify the instinctive modes 
of behaviour and their accompanying modes of instinctive experience 
under as many heads as may be convenient for our purposes of inter- 
pretation, and label them instincts of self-preservation, of pugnacity, 
of acquisition, the reproductive instincts, the parental instincts, and 
so forth. An instinct, in this sense of the term (for example the 
parental instinct), may be described as a specialised part of the 
primary tissue of experience differentiated in relation to some definite 
biological end, Under such an instinct will fall a large number of 
particular and often well-defined modes of behaviour, each with its 
own peculiar mode of experience. 
It is no doubt exceedingly difficult as a matter of observation and 
of inference securely based thereon to distinguish what is primary 
from what is in part due to secondary acquisition—a fact which 
Darwin fully appreciated. Animals are educable in different degrees; 
but where they are educable they begin to profit by experience from 
the first. Only, therefore, on the occasion of the first instinctive act 
of a given type can the experience gained be regarded as wholly 
primary; all subsequent performance is liable to be in some degree, 
sometimes more, sometimes less, modified by the acquired disposition 
which the initial behaviour engenders. But the early stages of 
acquisition are always along the lines predetermined by instinctive 
differentiation. It is the task of comparative psychology to distin- 
guish the primary tissue of experience from its secondary and 
acquired modifications. We cannot follow up the matter in further 
detail. It must here suffice to suggest that this conception of instinct 
as a primary form of experience lends itself better to natural history 
1 Origin of Species (6th edit.), p. 206. 
