Good Cop, Bad Cop Might Not Work

It’s a classic scene, found in nearly every television show and movie about crime and cops. There’s a good cop and a bad cop, and by combining brute force and gentle understanding, they get the criminal to confess to his crime. The problem is, this strategy might not actually work.

New research from the University of Portsmouth recently reenacted a good cop, bad cop scenario with research subjects. Students were assigned groups—they would either be telling the truth about a job they really had, or assigned a fictional job that they were going to lie about. With three days to prepare, the students were then asked detailed questions about their job. For both groups, the person asking the questions was neutral. It was the person taking notes who varied. Sometimes they were the good cop, nodding and smiling as the person spoke. In other cases they were bad, frowning and shaking their head during the note taking.

Christian Jarrett at Research Digest explains the results:

Here’s the headline result – the truth-telling participants gave more detailed answers than the liars, but only when the second interviewer provided a supportive presence. This runs entirely counter to the aggressive questioning styles so often portrayed in fiction. By creating a reassuring atmosphere, the second interviewer encouraged the honest interviewees to open up more, which made the the lack of detail given by liars stand out.

Of course, these are students, not criminals. Lives were not at stake, only a £5 reward for fooling the interviewers. Other studies have looked more directly at the good cop, bad cop dynamic and found a bit more support for the practice. And as we’ve covered before, undergrads respond very differently to classic psychology experiments than criminals do. But if the research stands, it could mean that bad cops aren’t helping anybody.

More from Smithsonian.com:

The Monocled World War II Interrogator
Like Pinocchio, When You Lie, Your Nose Gives You Away

Rose Eveleth | | READ MORE

Rose Eveleth was a writer for Smart News and a producer/designer/ science writer/ animator based in Brooklyn. Her work has appeared in the New York Times, Scientific American, Story Collider, TED-Ed and OnEarth.