Morningness versus eveningness arousal patterns in young adults.

The preference for morning versus evening time for activities requiring alertness was investigated. Responses from 9 individuals categorized as "owls" and 7 classed as "larks" based on their scores on the Morningness Versus Eveningness Questionnaire were compared to a group of 11 classified as "neither" on measures of sleep attitude and personality factors of arousal. No statistically significant differences were found; however, an item analysis yielded a statistically significant difference among the groups' responses on questions involving personal choices of sleep/wake schedules. This distinguishing aspect between the groups denotes the utility of subjective measures of preference. Our findings complement those from other subjective and experimental studies of "owls" and "larks" and add the important dimension of inquiring about personal preferences of subjects.