Commercials that feature sex and violence — or appear on programs with that kind of content — are less effective than those with neutral themes, according to a study published by the academic journal Psychological Bulletin.

Violent and sexual television programming impairs viewers’ memory because it diverts attention from the advertising, said Brad Bushman, a professor of communication and psychology at Ohio State University and co-author of the study, which analyzed the results of 53 previous experiments.

Results were similar when ads themselves contained sexual or violent content, he said.

“It never helps to have violence and sex in commercials,” Bushman said. “It either hurts, or has no effect at all.”