Individual differences in circadian activity rhythms were assessed and correlated with a number of measures of task orientation and time concern. Those who tend to be morning active completed the questionnaires more quickly than did others, expressed negative attitudes about wasting time, and scored higher on measures of achievement tendency and task leadership. Differences between college roommates in the tendency to be morning active vi'ere found to be related to negative evaluations of the roommate relationship. The results of this study suggest that the causes and effects of synchronized personal and social circadian rhythms warrant continued exploration.The purpose of this research was to explore the psychological correlates of individual differences in circadian activity rhythms. In achievement oriented American culture, time schedules, punctuality, and a quick pace tend to be valued highly (de Grazia, 1972;Friedman, 1969;Levine, West, & Reis, 1980; White, 1977;Whitrow, 1970), and early morning activity is connected both normatively and functionally to achievement success in many contemporary contexts (Melbin, 1978). Some people, however, are more alert and ready to perform during morning hours than are others. Because some people's circadian activity rhythms (i.e., the cycles of time of day the individual feels and performs best) are more compatible with these morning-based achievement concerns than are others', it was predicted that achievement orientation and time concern would be related to morning-active circadian rhythms.In general, the circadian curves of body temperature, speed, and accuracy on performance tasks, and feelings of arousal, alertness, and energy, reach a maximum in the afternoon and are lowest very
