A new study showed night owls have an edge over larks in terms of keeping their mind focused throughout the day.

The research done by a team at University of Liège in Belgium had 16 morning people, and 15 night people keep to their comfortable sleeping schedule, and pass simple attention tests twice a day. The testing was done 1.5 hours and 10.5 hours after waking regardless of the actual time of day. Scientists were studying the effect of sleep pressure, which builds up during the waking hours, on cognitive abilities.

While both groups performed equally well in the ‘morning’, the ‘evening’ test showed that late risers’ minds were quicker. Their reaction times were about 6% better than those of early risers, reports Science magazine. The result suggests that sleep pressure builds up faster in larks, said sleep researcher Philippe Peigneux, who led the research.

The paper gives a hint for risk estimate analysts on how sleeping patterns may affect the probability of accidents caused by human error, said David Dinges of the University of Pennsylvania School of Medicine in Philadelphia. At the moment, only the time of the day is taken into consideration.

The study also revealed an intriguing insight from brain scanning. In the later tests, the night owls showed greater activity in the brain region called the suprachiasmatic nucleus. It’s the ‘master-clock’ of the organism, which governs sleeping habits in the first place, telling us when to wake up and when to go to bed. Previously, it was thought that the master-clock operated independently from the sleep pressure mechanism, but the new evidence suggests that the two systems can affect each other.