Poker Study: Women injected with Testosterone - See Results Here

Testosterone is typically associated with aggressive, risky behavior. This being the case, you'd think that a poker player with higher testosterone would bluff often and take plenty of risks. But a team of researchers from the University of Cape Horn recently put this theory to the test by injecting female poker players with testosterone. And the results of their play, as you'll see below, were pretty shocking.

Background of the Study

The University of Cape Horn team noted that testosterone "motivates individual animals to strive for social dominance," particularly when it comes to ensuring food, shelter and mating partners. Furthermore, those who want to stay at the top of a social hierarchy need a good reputation, strength and social vigilance.

Relating this to humans, high testosterone has been correlated to stock market success (1), indicating that this male sex hormone may alter human behavior to maximize profits. But on the downside, testosterone is also believed to have played part in the U.S. banking crisis of 2008, where greedy, immoral bankers gambled with public funds (2). However, other studies conclude that testosterone is not always such an "immoral molecule" and can cause businessmen to be fairer in economic transactions to protect their reputation (3).

So the Cape Horn researchers wanted to figure out whether elevated testosterone causes individuals to strive for a better reputation or seek to maximize profits. And they chose bluff poker because it's a game where "concerns for status and resources uniquely collide."

Poker Testosterone Study Setup

Researchers set up the study by giving one group of young women a single 0.5-milligram dose of testosterone. After receiving their shot of anabolic steroids, the women played a game of bluff poker, where players try to randomly bluff opponents (regardless of hand strength) and avoid calling other players' bluffs. To accomplish these goals, players need to protect their reputation by not getting caught on cold bluffs, while also showing a willingness to call other players' bluff attempts to avoid blindly tolerating deception.

There was also a placebo group to compare the testosterone-taking group with. The idea was to see whether those injected with the hormone were more likely to make cold bluffs and call less, thus indicating a desire to maximize profits. However, if testosterone administration caused players to rely more on their hand strength — using less cold bluffs and calling more — then the hormone would indicate reputable, status seeking-behavior.

What happened in the Study?

Test subjects were measured according to the popular Nash equilibrium game theory. Researchers found that, after testosterone administration, players' bluffing became more exploitable since it was too dependent on hand strength, and cold bluffing decreased too (4). So, according to the Nash equilibrium, the testosterone subjects were actually using a less-profitable bluffing strategy than the placebo group. What's more is that the testosterone group also called more often, which, again, leads to fewer profits.

What can we conclude from the Poker Testosterone Study?

Contrary to what we previously discussed about high testosterone leading to greedy, risk-taking behavior, this hormone might not cause people to seek profits over their reputation. After all, the Cape Horn team found that testosterone-filled poker players make more-predictable bluffs and call too often. Their data suggests that testosterone causes humans to seek reputable status over quick profits.

It's very possible that humans mimic the animal kingdom in this way since alpha males and females do not display cheating behaviors, nor do they need to. They already have their choice of mating partners, food and shelter, so they don't have to cheat to get them. Perhaps this is why dishonesty is often associated with low testosterone levels (5). It could also be why the women in this study bluffed less, called more and used a less-deceitful, yet worse bluff poker strategy.

References
1. Coates, J. M., Gurnell, M. & Rustichini, A. Second-to-fourth digit ratio predicts success among high-frequency financial traders. Proc. Natl. Acad. Sci. USA 106, 623–628 (2009).
2. McDowell, J. E. Capital culture revisited: Sex, testosterone and the city. Int. J. Urban Regional Res. 34, 652–658 (2010).
3. Eisenegger, C., Naef, M., Snozzi, R., Heinrichs, M. & Fehr, E. Prejudice and truth about the effect of testosterone on human bargaining behaviour. Nature 463, 356–359 (2010).
4. Scientific Reports 6, Article number: 18096 (2016) doi:10.1038/srep18096
5. Dabbs, J. M., Jr. & Hargrove, M. F. Age, testosterone, and behavior among female prison inmates. Psychosom. Med. 59, 477–480 (1997).