A surprising cognitive difference between night owls and early birds

A recent study challenges the common belief that early birds outperform night owls intellectually. Published in BMJ Public Health, this research conducted by scientists at Imperial College London suggests that night owls may have a cognitive advantage over those who rise early.


To reach this conclusion, researchers analyzed data from over 26,000 British adults participating in the UK Biobank study. Participants underwent tests assessing their cognitive abilities, including intelligence, reasoning, memory, and reaction time. The results were then cross-referenced with participants' sleep habits, including duration, quality, and their chronotype (natural preference for specific bed and wake times).

The study reveals that individuals with a late chronotype, meaning those who prefer to go to bed and wake up later, perform better on cognitive tests. Their scores were 7.5% to 13.5% higher than those of early risers. These differences remain significant even after adjusting the data for various factors such as age, sex, smoking, and alcohol consumption.

However, the researchers emphasize that it is not a conclusion that all early risers have lower cognitive performance. According to Raha West, co-author of the study, these results reflect a general trend observed within the studied sample. Moreover, optimal sleep duration seems to be a crucial factor for maximal cognitive performance. Sleeping between seven and nine hours per night is associated with better memory, reasoning, and information processing abilities.

The study also highlights that insomnia, often considered a factor of cognitive decline, did not have the expected negative impact on participants' cognitive performance. This paves the way for future research to explore more specifically the aspects of sleep disorders and their influence on brain function.

Finally, although this study reveals an advantage for night owls, it underscores the importance of adopting regular sleep habits that suit one's own biological rhythm. Individual preferences for sleep timing, whether morning or evening, should be respected to maintain good cognitive health.