Blame a Sex Hormone for Feeling Uncooperative

Testosterone causes egotistical behavior and hinders cooperation

/ Author:  / Reviewed by: Chris Galloway, M.D.

(RxWiki News) While testosterone is best known as the male sex hormone, its presence is necessary in all of us to maintain our overall health and well being, yet those with increased levels of the hormone may have a hard time getting along with others.

New research suggests that imbalances of testosterone cause mood shifts—and those with heightened levels of the hormone tend to act more ego-driven and stubborn.

"Ask your doctors about your testosterone levels if you’re having trouble agreeing with others."

“Our behavior seems to be moderated by our hormones—we already know that oxytocin can make us more cooperative, but if this were the only hormone acting on our decision-making in groups, this would make our decisions very skewed.

“We have shown that in fact testosterone also affects our decisions,” notes corresponding author on the study Nicholas Wright, Ph.D., “by making us more egotistical.”

Dr. Wright, a scientific investigator at the Wellcome Trust Center for Neuroimaging, explains that the majority of the time, testosterone helps us navigate through tough decisions; however sometimes, in cases of excess, we become “blind” to the input of others, which inevitably leads to an uncooperative environment.

“When we are making decisions in groups, we tread a fine line between cooperation and self-interest—too much cooperation and we may never get our way, but if we are too self-orientated, we are likely to ignore people who have real insight," says Wright.

The researchers gained these insights while observing the effects of testosterone on thirty-four female volunteers. The testing occurred over two days with one day of testosterone supplementation and one day of placebo supplementation.

The women were grouped into pairs to begin a set of associative activities together. The duo assessed sets of photographs to determine which of two images had a centerpiece that greatly contrasted its environment. If the ladies agreed, they moved to the next image, and if not, they were instructed to come up with a joint decision.

When the women were both under placebo conditions, collaboration helped the women properly identify which photo contained the high contrast targets. Women supplemented with testosterone, however, did not cooperate as well and often held steady on their initial opinion, regardless of rationale.  

Co-author on the study, John Williams, Ph.D., also of Wellcome Trust, explains, "Cooperating with others has obvious advantages for sharing skills and experience, but we know it doesn't always work, particularly if one alpha male or alpha female dominates the decision-making.

“This result helps us understand at a hormonal level the factors that can disrupt our attempts to work together.”

Published in the Proceedings of the Royal Society B, this study was funded through the Wellcome Trust Centre, a global charity for human and animal health. No conflicts were reported during the course of the study.

Reviewed by: 
Review Date: 
January 31, 2012
Last Updated:
February 1, 2012