Pharos-Tribune

November 1, 2013

ROCK DOC: The science of detecting bluffs


Pharos-Tribune

---- — Experienced poker players know the basic odds of drawing the card they need to build a better hand. They also are good at estimating if their hand is likely to be better than those of the other players around the table. In other words, probability and statistics are built into the game of poker.

Proficient poker players are also good at a more human-based skill. They spend time and effort trying to read the faces of their opponents. The goal is to deduce whether other players hold strong or weak hands based on the way their faces look as they play. That element of poker isn’t based on statistics so much as on practical psychology.

As the famous Kenny Rogers song about gambling says, “Son, I’ve made a life/Out of reading people’s faces/Knowing what the cards were/By the way they held their eyes.”

A good poker player develops a “poker face” that minimizes how much his or her visage betrays the cards in play. That fact has been known as long as people have been betting on card games. But now there’s evidence recently discussed at the ScienceNews website that having a good poker face isn’t enough. It seems card players need to develop “poker arms” as well. Here’s the scoop — one that you may find useful in your next card game.

Psychology researchers at Tufts University acquired video of high-ranking poker players playing cards and making bets at the World Series of Poker. The researchers then had 78 college students try to predict whether the players had good or strong hands based on the way they looked.

First the students were shown video of the players’ upper bodies and faces. The students had no luck predicting the players’ hands based on that aspect of the video record. That’s just a long way of saying that the high-ranking poker players really did have “poker faces.”

Next, the researchers had the students study video of the players’ arms as the players placed bets on the tables in front of them. Using just that information, the students were often able to predict which players held strong hands versus which had weak ones. Those with good cards seemed to move their arms more smoothly compared to those with poor cards who were bluffing as they placed their bets. The bluffers appeared to have more awkward arm movements.

One thing I find quite impressive about that result is that the college students studying the video were not professional poker players. They may have played the odd hand of poker in their lives, but they were not experts. Nonetheless, these comparative novices could — on average — make a pretty good guess as to whether folks in the World Series of Poker in fact held good hands or not.

If the results of the Tufts study hold up, we’ll need to update the Kenny Rogers song. It’s not just the way poker players hold their eyes that can betray them, but the way they push their chips across the table.

Good luck with your next hand of cards.

Dr. E. Kirsten Peters is the author of “Planet Rock Doc.” This column is a service of the College of Agricultural, Human and Natural Resource Sciences at Washington State University. Peters can be reached at rockdoc.wsu.edu and on Twitter @RockDocWSU.