of the congenital endowment with which the child starts life. In their origin they are not influenced by the child's experience. They belong to the child before he has acquired any experience at all. It is characteristic of what is instinctive that it does not require to be learnt. Instincts are usually general, and common to all members of the same group. Some instincts, e.g. that of self-preservation, seem to be common to all living creatures. Others are common only to particular species. Instinctive modes of behaviour are general: we do not inherit special ways of acting.
It is often difficult to distinguish instincts from what the psychologist calls reflex actions. But there are two main lines of distinction. (1) Reflex actions always occur in a fixed and regular way in response to an external stimulus. They occur only when the stimulus is present, and when it is present they occur naturally and necessarily. Thus, when a bit of dust flies into the eye, certain movements of the eyelids take place which tend to get rid of the intrusive speck. Instinctive behaviour, on the other hand, does not need a definite stimulus to elicit it. It is excited as a way of dealing with a relatively complex situation. (2) Reflex actions are fixed and uniform. For the most part they are incapable of modification. We cannot modify the reflex changes which take place in the pupil of the eye in response to changes in the intensity of the light. To put it briefly, while instincts are adaptive and modifiable, reflex movements are not.
Instincts may be adapted to the environment, in order to secure the well-being of the individual and
