It’s well accepted that most of us are no better than a flip of the coin at seeing a lie. A classic experiment involves showing study subjects videotape of people, some of whom are lying, who say they did not steal $100; the subjects correctly guess the liars about half the time.

Dr. ten Brinke and her collaborators at Haas built on that experiment, with a twist: After the subjects watched the video and made their conscious assessments of who was lying, the researchers tried to measure the subjects’ unconscious reactions.

To do so, the researchers flashed images of someone already seen in the videotape — but this time in milliseconds, indiscernible consciously. The subjects then completed a word task that involved placing “truth” words (like truthful, honest, valid) and “lie” words (dishonest, invalid, deceitful) into their proper categories.

When study subjects were flashed a picture of a liar, they were significantly slower to lump words like truthful or honest into the “truth” category, but faster to lump words like deceitful into the “lie” category. The opposite was true when the subjects saw a truthful person. So, in general, the same people seemed better at detecting lies unconsciously than consciously. By scientific measures, the size of the effect was decidedly non-trivial, but not overwhelming.

There are many theories about why the ability to pick out liars gets lost in translation to consciousness. Dr. ten Brinke speculated that we tell one another little lies all the time — for survival, reproductive strategy, and so on — and that part of getting along socially is being able to let those harmless lies escape notice.