From the classroom to the cocktail party, opinions like “men are better at math,” “Asians make the best violinists,” or “women cannot be strong corporate leaders” are unpopular. Yet, says psychologist Mahzarin Banaji, we all carry prejudices like these. We just don’t admit to them, because in many cases, we don’t know they’re there. Banaji is interested in teasing out these unconscious — or implicit — attitudes about social group membership. Often, she says, they stand in contrast to the feelings and beliefs that we comfortably trot out in public. Banaji has been studying implicit attitudes for nearly 20 years. She is now moving her work beyond the laboratory and into arenas like law or medicine, where attitudes and prejudices might affect decisions daily. “These biases may be more pervasive than we had thought,” she says. “They often sit in opposition to conscious beliefs, and if that’s the case, then I think [the work] asks, with a new urgency, what it is that we wish to do in a variety of domains.” Banaji is Richard Clarke Cabot Professor of Social Ethics at Harvard and Carol K. Pforzheimer Professor at Harvard’s Radcliffe Institute for Advanced Study.