Rats avoiding mental workloads offer clues to lower motivation in depression

Sometimes, hard work can be measured in sweat. Weeding a garden, painting the house or hooking golf balls out of the woods to win the Masters can leave a person physically wrung out.

But hard work isn’t only about muscles. It takes place between people’s ears, too. Mental efforts, whether dedicated to writing a flawless sentence, figuring out how to respond to an e-mail or solving a long list of algebra problems, can be just as hard as Bubba Watson’s swinging a club at Augusta National.