In poker, your arms give you away

 Michael Slepian, Associate Professor of Leadership and Ethics at Columbia University, studies the psychology of secrecy. He hit on the idea of studying poker players to determine whether the motions made by poker players as they placed their bets could reveal whether the players’ cards were good or bad.

In a series of three studies, Slepian asked undergraduates to look at clips of players from the 2009 World Series of Poker. In some of the clips, the students could see the full body (from the table up) and face of the players as they made their bets. Another set of clips showed only the chest and head (face) of the players. A third set of clips showed only the players’ arms as they pushed chips in on the table. The students were then asked to judge the quality of the poker hands—from very bad to very good—based on the clips they saw.

When judging the first two sets—those that included the heads and faces of the players—the students were no better than chance at guessing the quality of the players’ hands. In fact, when they studied players’ faces, their judgements actually dropped to below chance levels. Faces, it turns out, may actually give more false than useful information. But when the students looked at clips showing the motion of arms alone, their performance shot up. Even people who had no prior knowledge of poker seemed suddenly able to tell with some accuracy whether a player had a strong or weak hand. The players with the better hands executed their moves in a fluid manner and the students instinctively picked up on it. Apparently, smooth body movements suggest confidence; anxiety disrupts the smoothness.

At birth, our brainstems—the lowest and most primitive part of our brains—control our arms. That connection endures. We don’t think about the way we’re moving our hands and arms. For poker players, those movements can betray their carefully arranged facial expressions—their poker faces.

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