Lacking brain receptor, slacking monkeys become workaholics Just in time for back-to-school season, researchers have turned procrastinating monkeys into workaholics by suppressing a gene that encodes a receptor for a key brain chemical. The receptor, for the neurotransmitter dopamine, is important for reward learning. By suppressing it, researchers at the US National Institute of Mental Health (NIMH) in Bethesda, Maryland caused monkeys to lose their sense of balance between reward and the work required to get it. "Like many of us, monkeys normally slack off initially in working toward a distant goal. They work more efficiently—make fewer errors—as they get...