Instinct and Motivation as Explanations for Complex Behavior

Abstract

Few behaviors are truly reflexive, and those that are are not the behaviors with which most animals make their livings. If you have any residual doubt about that assertion, recall the characteristics of reflexes as studied by Sherrington early in this century (reprinted in 1947). They are innate, they lack spontaneity, are stimulus bound, and stereotyped. That is, a particular set of them occurs in all animals of the same kind as the outcome of their genome and its realization in normal development (innateness). Reflex effects (exitatory or inhibitory) are always elicitable from an intact nervous system by some combination of the duration and repetition of their stimulus provided that the stimulus is the right kind (“adequate” in Sherrington’s terminology) and strong enough (stimulus binding).1 And the afferent input is necessary; without it the behavior does not occur (no spontaneity). The stimulus determines the frequency and form of the behavior, and the form is the same from episode to episode of its elicitation and across animals of the same kind (stereotypy). The taxes and kineses of the older animal behaviorists (see Fraenkel & Gunn, 1961) are the same kinds of behavior in all respects.