Do differences in sleep cycles between boys and girls help explain the gender performance gap? That's the theory behind a paper released this summer by the Institute for the Study of Labor, a private, independent research institute based in Germany.
The study is believed to be the first study to find a connection between later school start times and improved academic performance by boys relative to girls.
Researchers from the University of California, Davis, studied data from a group of secondary schools in Eastern Europe where students alternate school start times each month. For example, one month middle school students would start class at 7:30 a.m., and high school classes would begin at 1:30 p.m. Then the following month they would switch start times. During each rotation, students had the same teachers and took their courses in the same order.
The researchers looked at all the students' grades from month to month and compared their performance in the afternoon versus the morning from 2008 to 2014.
They found that, while girls outperform boys overall, the gender gap is narrower during the afternoon classes than it is during the morning classes. The work builds on previous studies, which found that girls deal with sleep deprivation more successfully than boys and are more likely to be early risers, while boys' circadian rhythms make them more likely to stay up later and wake later in the morning.