If you’d like your kid to get better grades in school, put their desk near a window. Cognitive development experts at Carnegie Mellon University found that kids who took exams in classrooms with lot of natural light saw their test scores improve by 25%! And their research also suggests that kids who study at home near a source of natural light retain more information.

So what’s the link between sunlight and more brainpower? Dr. Anna Fisher, who led the study, says humans are simply hardwired to be more productive in natural light. The sun’s rays are in the blue spectrum. That suppresses the sleep hormone melatonin and stimulates the hormone serotonin, which makes us more alert, boosts cognitive ability, focus, and energy. And those alertness-boosting effects take effect almost immediately. And studies show workers are more productive in natural light, too.

So if you and your kids are working and studying at home, make sure they’re near a window!