Effects of time of day and personality on intelligence test scores

Abstract

The present investigation was designed to study the time of day effects on intelligence test performance in subjects varying on extraversion and neuroticism dimensions of personality according to a procedure known as ‘zone analysis’. A factorial design involving four levels of personality and three day timings with repeated measures on the second factor was replicated 15 times. Cattell's Culture Fair Intelligence Test (CFIT), Scale III, Form A served as the criterion measure. The study supports the following conclusions: (1) the performance on the CFIT was better in the evening (1900 hours) than in the morning (0900 hours) and afternoon (1400 hours) except for topology subtest; (2) personality did not produce any effect on CFIT performance; (3) personality and time of day did not interact in their effects on CFIT performance.