Association of chronotype and social jetlag with human non-verbal intelligence.

The aim of this study was to evaluate the effects of chronotype and social jetlag (SJL) on intelligence. Subjects were aged 14-25 years (n = 1008). A significant effect of intelligence on academic performance, as measured by the Raven's Standard Progressive Matrices test, was found (F2,917 = 11.75, P < 0.0001, η2 = 0.03). When SJL was less than 2 hours, the intelligence of people with late chronotype was found to be higher than that of subjects with early and intermediate chronotypes (F2,305 = 3.12, P < 0.05, η2 = 0.02). A negative effect of SJL on the results of intelligence testing was noted only in subjects with late chronotype (F2,536 = 2.61, P < 0.05, η2 = 0.02). Our data suggest that people with late chronotype have a higher level of intelligence, but these advantages disappear when SJL ≥2 hours.