Study Sheds Light on How Darkness Produces Dimwits

The structure of the brain, and even the ability to learn and remember knowledge, may be hampered by spending too much time in dim light, researchers at Michigan State University have concluded, in a just-published, first-of-its-kind study likely to reinforce why bright is a synonym for smart.The researchers exposed Nile grass rats to dim and bright light for four weeks, studying the effect on the rodents’ brains. The rats—which like humans are diurnal and sleep at night—lost a