d biological
connotation in terms of behaviour. But the connecting link between
biological evolution and psychological evolution is to be sought,--as
Darwin fully realised,--in the phenomena of instinct, broadly
considered. The term "instinctive" has also a psychological
connotation. What is that connotation?

Let us take the case of the swimming duckling or the pecking chick,
and fix our attention on the first instinctive performance. Grant that
just as there is, strictly speaking, no inherited behaviour, but only
the conditions which render such behaviour under appropriate
circumstances possible; so too there is no inherited experience, but
only the conditions which render such experience possible; then the
cerebral conditions in both cases are the same. The biological
behaviour-complex, including the total stimulation and the total
response with the intervening or resultant processes in the sensorium,
is accompanied by an experience-complex including the initial
stimulation-consciousness and resulting response-consciousness. In the
experience-complex are comprised data which in psychological analysis
are grouped under the headings of cognition, affective tone and
conation. But the complex is probably experienced as an unanalysed
whole. If then we use the term "instinctive" so as to comprise all
congenital modes of behaviour which contribute to experience, we are
in a position to grasp the view that the net result in consciousness
constitutes what we may term the primary tissue of 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,[166] 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. Thi