Preferences and Behaviors of Morning and Night People: Self-Report

Abstract

The history of individual differences for those who might be described as morning or night people (a.m.-p.m. people) dates back at least to O'Shea ( 7 ) , who tried to determine the time of day when people were at their best and their worst and found individual differences. There has been some debate as to how many categories and types exist. Freeman and Hovland ( 3 ) proposed four types, classified as to patterns of body temperature. Kleitrnan ( 5 ) on the same bases argued for two types. Arguments have been made that a.m.-p.m. people have different personality profiles (6), perform better in their respective time slots ( I ) , do not vary in total amount of sleep, but do vary in the times that they retire and rise, with a.m. people doing these earlier ( 4 ) . Very often in these studies and classification schemes body temperature was used as the categoriter, noting earlier ~ e a k temperatures characterize a.m. people. The present study using the self-report questionnaire yields a descriptive profile of preferences and behavioral differences for a.m.-p.m. cypes and examines independent item cluster ~rof i les for rhese groups using factor analysis. A 45-item questionnaire was administered to 230 undergraduates; 180 of these were completed as directed and analyzed. A factor analysis using principal factoring without iteration, showed that Factors 1 and 2 accounted for 12.7 and 10.4% of the total variance, respectively. Items correlated with Factor I were the time a person returned home after an evening out (0.51) and the time a person went to bed on the weekend (0.37). Factor 1 seems to refer to a night person. Items that correlated significantly with Factor 2 were quantity of breakfast eaten during the week (-O.63), number of days breakfast was eaten during the week (-0.57), number of days breakfast was eaten during the weekend (-0.40), and size of breakfast the person ate (-0.52). Factor 2 seems to refer to people who dislike breakfast. Using a cross-tabulation procedure the variable of self-description of morningness or eveningness was crossed with the other 44 variables. The following items had significant values of chi squared ( p > .05) for those who consider themselves morning people: drink alcoholic beverages less, get up earlier during the week, get up earlier on the weekends, eat breakfast on more days during the week, accomplish more work in the morning, prefer to work in the mornings. and enjoy soft music. Self-reported morning people seem to require less st~mulus input (i.e., drink alcohol less and enjoy softer music) than night people and t h ~ s agrees with Eysenck ( 2 ) who reported lower arousal thresholds for day people. Coos~stent with the self-reported category morning people do prefer to be more active earlrer, i.e., getting up earlier, accomplishing more, and eating more breakfast. The relatively strong appearance of a breakfast-disliking factor was surprising. It has not appeared as a factor in the a.m.-p.m. literamre. It may indeed be unrelated as the only direct link was that a.m. people eat breakfast more on weekdays.