Depending on your chronotype, that is to say whether you are a morning person or an evening person, your cognitive abilities do not work in the same way. Reasoning, memory, processing speed: sleep influences your brain and your internal clock on all axes. A British study has revealed who is better off intellectually between night owls and early risers.
A British study that overturns preconceived ideas
For decades, early risers have been valued as models of efficiency and success. But a large study carried out by Imperial College London seriously challenges this stereotype. Published in the journal BMJ Public Healthit is based on data from more than 26,000 participants who completed reasoning, memory and intelligence tests. Each of them also indicated whether they considered themselves an early riser, night owl, or somewhere in between.
The results are clear: night owls obtain cognitive scores 13.5% higher on average than early risers. As for the “intermediate” profiles, they do better than the morning people… but remain behind the night owls. The study also took into account factors such as age, gender, lifestyle habits, and general health to isolate the effect of chronotype on cognitive functions.
However, the study remains observational. This means that it highlights correlations, without being able to say with certainty that being a night owl causes better intellectual performance. As lead researcher Dr Raha West recalls: “This does not mean that all early risers have poorer cognitive performance. Our results reflect a general trend“.
Why are night owls more intellectually brilliant?
If night owls seem mentally sharper, it’s no coincidence. Their brains work differently at certain times of the day. Studies on the circadian rhythm have demonstrated that our vigilance, our working memory and our analytical skills are not constant: they vary according to the time of day and the chronotype.
Night owls, often more alert in the late afternoon or evening, perform cognitive tests in slots that correspond to their peak performance. On the other hand, early risers are already experiencing a drop in energy at these same times, which could explain their lower results.
Another explanation put forward: evening people have sometimes developed different mental strategies to compensate for a lifestyle that is out of step with social standards, often geared towards morning productivity. This would promote, in some people, a greater capacity for cognitive adaptation.
The true impact of sleep on the brain
Beyond the chronotype, it is above all the quality of sleep which seems to play a key role. Researchers observed that sleeping between 7 and 9 hours per night significantly improved memory, information processing speed and executive functions. Conversely, less than 7 hours or more than 9 hours harms cognitive performance.
Sleep allows the brain to consolidate learning, evacuate metabolic waste and restore emotional balance. These are all crucial mechanisms for maintaining a good intellectual level. And these benefits apply to both early risers and night owls, as long as they get enough sleep.
Respecting your biological rhythm, the real key
The mistake would therefore be to want to make everyone fit into the mold of waking up at 6 a.m. To function at your best level, you must first listen to your own body. A night owl forced to get up early accumulates fatigue, loses lucidity, and ends up seeing his performance drop. Conversely, an early riser who hangs around in the evening also pays the price for out-of-sync sleep.
Respecting your chronotype, combined with a stable sleep duration, is the winning duo for a brain in great shape. “You need to sleep enough, not too much, not too little. It’s essential for your brain to stay healthy and function optimally“, concludes Dr. West.