ABSTRACT
In Chapter 2, Barrett outlines research which is perhaps particularly marked by its objectivity and scientific rigour. The data discussed are those resulting from studies in which animals are exposed to carefully controlled experimental conditions. Psychologists have long used such methods to investigate how environmental circumstances can influence the behaviour exhibited by animals. Barrett's review of what is often now designated 'behavioural pharmacology' shows how research has established that principles which are important in understanding behaviour in its own right can also be important for an understanding of the behavioural effects of drugs. Whatever the direct biochemical or physiological effects of a drug might be, it has thus become clear that the effect which the drug exerts on overt behaviour can differ as a result of the experimental conditions controlling the behaviour. For example, the rate at which a pattern of operant behaviour occurs, which is largely the result of the environmental conditions to which an animal is exposed, can be an important determinant of the behavioural effects of stimulant drugs, influencing not just the size of any drug effect but even on occasion its direction. Barrett also discusses such other factors as discriminative control of behaviour, the nature of the event which maintains behaviour, and the prior behavioural and pharmacological history of an animal, all of which can exert powerful effects on the behavioural outcome of drug administration.
