Alcoholics have trouble understanding jokes, but they may be missing out on much more than a chance to laugh.

German neuroscientists showed 29 alcoholics and 29 healthy control subjects the introduction to a joke and then a choice of punch lines—only one of which made logical sense and was funny. Whereas 92 percent of the nondrinkers chose the correct punch line, only 68 percent of the drinkers did. “The ability to understand jokes is an example of complex social cognition,” explains Jennifer Uekermann of Ruhr University Bochum. “It involves detecting incongruity—what's wrong or funny about the story—and putting oneself in another's place.”

An alcoholic's problems with social cues are consistent with the “frontal lobe hypothesis,” which postulates that damage to the prefrontal cortex—known to be vulnerable to alcohol's toxic effects—leads to behavioral deficits. Most other studies of alcoholics’ brain function have concentrated on perceptual problems caused by such damage, Uekermann says. But when a person has deficits in social cognition, he or she has difficulty getting along with and working with other people. A better understanding of how problem drinkers are impaired could help improve rehabilitation programs for alcoholics.