ABSTRACT
Preliminaries In this chapter it is intended to supply, in general terms, a biological background to the specialized study of cognition, both at the mole cular and at the molar levels. Work in this field has been done mainly by ethologists, or biologists who have studied animal behaviour. Space forbids that we should explore these remoter levels of cognition other than in general terms, but the psychologist must be familiar with what is being done in allied fields of endeavour, and constantly bear it in mind.
