HANDEDNESS AND SLEEP DURATION Robert A. Hicks, Robert J. Pellegrini and James Hawkins (San Jose State University)
The purpose of this note is to report and discuss briefly a relationship which we have observed between handedness category, i.e., either left-, mixed-, or righthanded and habitual sleep durations. For a fair amount of time we have been conducting ongoing research programs on both handedness effects (e.g., Hicks and Pellegrini, 1978b; Hicks, Pellegrini and Evans, 1978) and the behavioral correlates of extremes in sleep duration (e.g., Hicks and Pellegrini, 1977). In scoring and tabulating these separate sets of data, it became apparent to us that individuals who we classed as mixed-handed on the basis of their responses to the BriggsNebes (1975) handedness scale, seemed to show greater extremes in their sleep durations than either left- or right-handed individuals. Since extremes in normal sleep duration have recently been linked to pronounced differences in personality traits (e.g., Hartmann, 1973; Spinweber and Hartmann, 1976), differences in urinary excretions of MHPG and 17-0HCS (Spinweber and Hartmann, 1977) and rather pronounced differences in stress-Pattern A behavior (Hicks, Pellegrini and Hawkins, 1978) we felt that this fortuitous observation was worth quantifying, as a potential means of identifying for future research, behaviors that might be unique to mix-handed individuals.
METHODS AND RESULTS
First, more than 900 college students were tested using the Briggs-Nebes (1975) modification of Annett's (1967) handedness scale and a sleep duration questionnaire that asked, "How many hours do you sleep each night?," "How long have you been experiencing this duration of sleep?," and "Are you satisfied with this amount of sleep?" Using the scoring criteria suggested by Briggs and Nebes, we identified 60 lelft-handed, 36 mixed-handed, and 125 right-handed (all of whom scored a perfect + 24) individuals, who reported both that they had experienced their sleep duration for at least the preceding 6-mo. period and who claimed that they were satisfied with their amount of sleep. For each subject, we recorded two parameters of sleep duration, i.e., the number of hours of sleep/night, and the absolute deviation of their nightly sleep duration from the mean computed from normative data provided in a recent study (Hicks, Pellegrini, Hawkins and Moore, 1978). The means, standard deviations and the Fs derived from one-way ANOV As that were computed to Cortex (1979) 15, 327-329.
R. A. Hicks, R. ]. Pellegrini and ]. Hawkins
test the differences between handedness groups for each variable are listed in Table 1. TABLE I
The Means, Standard Deviations and ANOVA Results for the Two Sleep Duration Parameter for the Various Handedness Groups Sleep duration Parameter Hours of sleep/night Absolute deviation score
Left Mean ± S.D. 7.3 1.1
Mixed Mean ± S.D. 6.7 1.5
Right Mean ± S.D.