Time of day effects on performance in a range of tasks

Abstract

Performance on eight tasks ranging from novel laboratory tests to highly practised familiar skills was measured at five times of day between 8 AM and 9 PM. Five tasks showed a consistent tendency for improvement in efficiency from 8 AM through 9 PM; in one task there was deterioration; and in the remaining two the effects were not significant. The results suggest that the observed trends are related to the underlying state of arousal as indicated by body temperature. © 1967, Psychonomic Press. All rights reserved.