Percept Mot Skills. 2007 Feb;104(1):335-8
Morningness-eveningness correlates with verbal ability in women but not men.
Killgore WD, Killgore DB
Individuals differ along a continuum of preference for diurnal activity level, known as Morningness-Eveningness. Some evidence suggests that an Eveningness orientation (i.e., preference for later rise and bed times) is weakly associated with higher cognitive ability, but no studies have examined this relationship using clinically accepted, psychometrically valid measures of cognitive ability. The present study examined the correlation between Morningness-Eveningness with scores on the Wechsler Abbreviated Scale of Intelligence (WASI) of 54 healthy volunteers. Lower Morningness (i.e., Greater Eveningness) orientation was correlated (r = -.23) with higher Verbal IQ for the entire sample. When the data were examined separately by sex, the correlation between Morningness-Eveningness and Verbal IQ was significant for women (r = -.44) but not for men (r = -.09).