RELATIONSHIPS BETWEEN ABILITY AND PERSONALITY - 3 HYPOTHESES TESTED

This paper describes some studies of the interrelationship of personal ity and intelligence using data from a survey of Scottish farmers. (N = 210). Subjects completed the NEO Five Factor Inventory, Raven's Stan dard Progressive Matrices and the National Adult Reading test (NART). We address three hypotheses from the recent literature: that personali ty is more differentiated at high than at low levels of ability; that mental abilitites are more differentiated at low than at high levels o f neuroticism, and that intelligence affects the correlation between c ertain airs of personality dimensions. Evidence is found for increased differentiation of neuroticism (N) and Openness (O) at higher levels of ability. It is also found that the level of N moderates the associa tion between different types of mental ability. The Raven-NART correla tion is depressed in low-N compared to high-N subjects; evidences is a lso found of a nonlinear relationship between ability and trait variab les for N and O. No significant effects of ablity on correlations betw een pairs of personality dimensions are found; in particular there is no support for the hypothesis that intelligence affects the correlatio n between extraversion and conscientiousness. We also examine the effe cts of ability on reliability of the NEO dimensions. It is found that Cronbach alpha values are lower for lower ability subjects, particular ly for the I dimension. The consequences of this in counfounding effec ts due to personality differentiation and differential reliability and the resulting difficulty in interpreting experimental observations in this area are discussed. Some possible experimental approaches to thi s problem are proposed.