Péter Ujma1,2, Tanja G. Baudson3,4, Róbert Bódizs1,2, Martin Dresler5
Scientific Reports (2020) 10:7105 Free full-text 
DOI: 10.1038/s41598-020-62917-9


1Institute of Behavioural Sciences, Semmelweis University, Budapest, Hungary

2National Institute of Clinical Neuroscience, Budapest, Hungary

3Mensa in Germany, Cham, Germany

4Institute for Globally Distributed Open Research and Education (IGDORE), Bali, Indonesia

5Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre, Nijmegen, Netherlands


Sleep-wake patterns show substantial biological determination, but they are also subject to individual choice and societal pressure. Some evidence suggests that high IQ is associated with later sleep patterns. However, it is unclear whether the relationship between IQ and later sleep is due to biological or social effects, such as the timing of working hours. We investigated the association between habitual sleep timing during work days and work-free days, working time and membership in Mensa, an organization of highly intelligent individuals (IQ ≥130) using a sample of 1,172 adults split between Mensa members and age- and sex-matched volunteers from a large web-based database. We found no difference in chronotype, and the later sleep timing of Mensa members on work days was fully accounted for by later work start times. our results indicate that later sleep timing in those with higher IQs is not due to physiological differences, but rather due to later work schedules. Later working times and the resulting lower social jetlag may be one of the reasons why higher IQ is associated with lower prospective morbidity and mortality