ABSTRACT
Ivan Petrovich Pavlov symbolises more than anyone else the fundamental concern of psychology with general laws, with environmental modification of behaviour, and with the experimental study of functional relationships. Experimental psychologists often seem quite unaware of the problems created by individual differences; personality theorists seem equally unconcerned with the lack of relationship between their concepts and those of the experimentalists. The most usual argument made by the experimental psychologist, however, is probably along these lines. Psychopharmacology has nearly always adopted the simple experimental paradigm based on the assumption that these effects could be traced by comparing group performance under placebo conditions with group performance under drug conditions; failure to find significant effects has usually led to retention of the null hypothesis. In the latter, the main dimensions were tentatively identified with concepts in experimental and general psychology, deductions were made from the identification, and experiments were carried out to test the value of these deductions.
