Study: Too much testosterone makes you overconfident and impulsive

Geschatte leestijd: 5 minuten High levels of testosterone can make one overconfident and impulsive. Being wrongly convinced of one’s own rightness turns out to be a particularly unpleasant trait.

Know-it-all Bodybuilders

We saw Arnold Schwarzenegger overflowing with self-assurance in the classic Pumping Iron. The reason I personally found it just on the edge of arrogance and not over it, is the fact that he proved his words. Based on several studies, nicely summarized in a recent article by the NY Times, we might suspect that certainty about one’s own correctness could indeed be a characteristic of more bodybuilders. Purely in terms of testosterone levels. These studies point to the positive correlation between testosterone and self-assurance, overconfidence, and impulsivity. Unreasonableness due to hormones is thus not the exclusive right of women.

Sure but Wrong

In Canadian research from 2008 on self-assurance, various skill tests were conducted where participants had to assess how they had performed compared to others [1]. It was striking that gender showed a strong correlation. Men were much more inclined to think they had done better on the tests than others. One of the arguments to point to testosterone as a cause came from research in 2010 by researchers from the University of Oregon and the University of Texas[2]. They discovered a negative correlation between testosterone levels and activity in the orbitofrontal cortex. This part of the brain acts as a sort of internal control system. When this area is more active, you will think longer about the consequences of certain actions and the correctness of certain thoughts and ideas. More testosterone would mean feeling less need to doubt one’s own correctness, thereby causing an unjustified feeling of self-assurance. Earlier research from 1994 also provided a nice indication [3]. Male and female college students were both asked to answer questions and then indicate how confident they were about the correctness of their answers afterward. In case the correct answer was given, both genders rightfully gave themselves high scores. However, in the case of incorrect answers, it turned out that women rightfully doubted while most men filled in ‘certain’ or ‘very certain’.

Ball and Bat

No, it’s not a reference to shrinking balls, but to one of the tests used to measure the effect of testosterone. Researchers from Kiel University and Oxford University had a group of adults take a so-called cognitive reflection test (CRT) last year [4]. In this study, various test questions were asked. One such question reads as follows: A bat and a ball together cost €1.10. The bat costs one euro more than the ball. How much does the ball cost? Although I suspected it was a trick question, I quickly answered the question myself with ’10 cents’. However, if the ball costs 10 cents and the bat is one euro more expensive, then it costs €1.10. Plus 10 cents for the ball and you end up with €1.20 instead of €1.10. So, the ball costs 5 cents and the bat €1.05. However, apparently I don’t have to be ashamed. Even at prestigious universities like Harvard and Princeton, less than 30 percent of students answered the question correctly [5]. But it was intentionally a trick question. The test is not so much about whether you answer the question correctly, but about the certainty you feel while answering. With a little less testosterone, I might have thought for more than 1 second before giving an answer. In the study from Kiel University, both men and women overestimated the extent to which they had answered the questions correctly, which is not surprising when deliberate trick questions are asked. However, women expected to have performed just as well as other women. Men, on the other hand, thought they had done much better than others. These results are confirmed in a recent study [6]. Gideon Nave from the University of Pennsylvania and colleagues had 243 men apply gel to their arms, shoulders, and chest. Half received a testosterone gel and the rest received a placebo gel. The men then continued their day until four and a half hours later when testosterone levels peaked and they returned to the lab. They then performed various tests including a math test, a mood test, and the aforementioned CRT test. The men who received testosterone gel answered the ball-and-bat question incorrectly 35% more often. They also rushed in their incorrect judgments, while, oddly enough, they needed more time for the correct answers.

Testosterone Makes (Women) Stubborn

Okay, the above title sounds a bit wrong and sexist, but it turns out to be a factual observation. Researchers from the University of Birmingham in Britain looked at the influence of fluctuating testosterone levels in women [7]. For the study, women had to detect and point out a fuzzy pattern on a busy screen. When women had been given oral testosterone (instead of a placebo), they were much more likely to ignore the opinions and input of other women. Testosterone gave them more certainty about their own correctness, even when they were wrong.

Overconfidence is Dangerous

The risks of such overconfidence were demonstrated by researchers from Claremont Graduate University. They showed that this overconfidence can have adverse effects, including on financial markets. The researchers gave 140 male traders testosterone gel or a placebo. The men who received testosterone gel tended to overvalue certain things while overlooking negative things that would justify a lower rating. This could create the risk of a bubble of overvalued assets. Apparently, during the dot-com bubble, traders were heavily on the test. However, the traders in the study were not allowed to provide real valuations.

Success through Hubris

Often you see that people are successful by overflowing with self-assurance and overconfidence. Being right is often less decisive than appearing convincing and self-assured in many situations. This results in the familiar ‘I-always-know-best managers’ and presidents like Trump. Situations where self-assurance is seen as strength whether one is rightfully or wrongfully convinced of one’s own rightness. So, it doesn’t necessarily have to be disadvantageous in a world where (the illusion of) strength is valued. However, it does mean that men are also susceptible to unreasonableness due to hormonal fluctuations.

References

1. What makes you think you’re so smart? Measured abilities, personality, and sex differences in relation to self-estimates of multiple intelligences.
2. By Visser, Beth A.; Ashton, Michael C.; Vernon, Philip A. Journal of Individual Differences, Vol 29(1), 2008, 35-44.Mehta PH, Beer J. Neural mechanisms of the testosterone-aggression relation: the role of orbitofrontal cortex. J Cogn Neurosci. 2010 Oct;22(10):2357-68. doi: 10.1162/jocn.2009.21389. PubMed PMID: 19925198.
3. Highly confident but wrong: Gender differences and similarities in confidence judgments. Lundeberg, Mary A.; Fox, Paul W.; Punćcohaŕ, JudithJournal of Educational Psychology, Vol 86(1), Mar 1994, 114-121.
4. Ring P, Neyse L, David-Barett T, Schmidt U. Gender Differences in Performance Predictions: Evidence from the Cognitive Reflection Test. Frontiers in Psychology. 2016;7:1680. doi:10.3389/fpsyg.2016.01680.
5. Cognitive Reflection and Decision Making. Shane Frederick Reviewed work(s): Source: The Journal of Economic Perspectives, Vol. 19, No. 4 (Autumn, 2005), pp. 25-42
6.  Nave, G., Nadler, A., & Camerer, C. (2017) Single dose testosterone administration impairs cognitive reflection in men. Psychological Science (forthcoming)
7. Testosterone disrupts human collaboration by increasing egocentric choices. Nicholas D. Wright, Bahador Bahrami, Emily Johnson, Gina Di Malta, Geraint Rees, Christopher D. Frith, Raymond J. Dolan Proc. R. Soc. B 2012 -; DOI: 10.1098/rspb.2011.2523. Published 1 February 2012