A Single Dose of Testosterone Impairs Cognitive Reflection in Men
From watching TV, listening to the radio, and reading ads in magazines, it would seem to the casual observer that men deciding to take testosterone are simply taking “natural” substances that are benign, that have no negative side effects, and that have total upside. Regaining lost youth. Improving sexual prowess. And, more.
We say “NOT SO FAST”. An important study was published in August 2017 in the Psychological Science Journal that reveals that taking testosterone can have negative side effects beginning with the very first dose. This study, conducted by Gideon Nave, Amos Nadler, David Zava, and Colin Camerer demonstrated but one of the negative side effects that accompany testosterone use.
In nonhumans, the sex steroid testosterone regulates reproductive behaviors such as fighting between males and mating. In humans, correlational studies have linked testosterone with aggression and disorders associated with poor impulse control, but the neuropsychological processes at work are poorly understood.
Building on a dual-process framework, we propose a mechanism underlying testosterone’s behavioral effects in humans: reduction in cognitive reflection. In the largest study of behavioral effects of testosterone administration to date, 243 men received either testosterone or placebo and took the Cognitive Reflection Test (CRT), which estimates the capacity to override incorrect intuitive judgments with deliberate correct responses.
Testosterone administration reduced CRT scores. The effect remained after we controlled for age, mood, math skills, whether participants believed they had received the placebo or testosterone, and the effects of 14 additional hormones, and it held for each of the CRT questions in isolation.
Our findings suggest a mechanism underlying testosterone’s diverse effects on humans’ judgments and decision making and provide novel, clear, and testable predictions.
This new study comes on top of a number of other studies that identify the negative physical and psychological side effects of testosterone.
For those interested in digging into the science behind this study, you can get access to all of their work at: goo.gl/FA6XC3
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