Given the particular focus of this paper, and considering that studies relating to all of the above have been reviewed elsewhere (Griffiths, 1991), clearly not all of these areas need to be covered in detail. However, selected examples of relevant research will be described.MethodsThe conclusion that different methods produce the same results and tend to give support only to the null hypothesis is regarded by Eysenck (e.g. 1978, P. 145) as artifactual. He claims that introducing personality into the picture "often serves to demonstrate quite clearly that two methods apparently equal in effectiveness, differ sharply, one being much better for introverts, the other for extraverts" (1984, p. 185).The truth of this claim is demonstrated by findings from a series of studies undertaken by Leith (e.g. 1969, also reported, 1974), one of which investigated differences in responses to "reception learning" (i.e. standard deductive teaching of principles by direct instruction) and "discovery learning" (i.e. the inductivemethod in which students are asked to fmd out principles and results for themselves). Leith investigated the hypothesis that "the greater readiness of extraverts to become bored by routines but likely to respond to stimulus variation, and of introverts to be disturbed by changes of set but able to maintain attentiveness to a highly prompted task, would result in a methods by personality interaction" (cited in Eysenck, 1978, p. 145).A carefully prepared course (in genetics) was delivered to 211 students in randomly assembled treatment groups. One group learned from a program prepared in the form of direct instruction (reception learning), while the other learned from a discovery program. The discovery program was organised so that a complex whole was given first and then analysed, while the reception learning version built up the complex whole step by step. Both programs contained exactly the same contentand the same examples were covered in each version. The difference was essentially one of induction or deduction. A post-test on the material taught and relevant transfer items was given one week after the completion of the course, and a retention test was given after a further four weeks.Both sets of scores showed significant treatment x extraversion interactions (p