The image of testosterone-driven decision making is one of brutish oafs blundering through matters in an immoral and insensitive manner.  It’s a perspective that is challenged by a new study from the University of Texas at Austin, which suggests that testosterone might actually make people more sensitive to moral norms.

The researchers set out to explore the hormonal underpinnings of moral reasoning, and particularly to go beyond previous research and explore the biological factors, and especially the role testosterone plays in decision making.

“There’s been an increasing interest in how hormones influence moral judgments in a fundamental way by regulating brain activity,” the researchers explain. “To the extent that moral reasoning is at least partly rooted in deep-seated biological factors, some moral conflicts might be difficult to resolve with arguments.”

The trolley dilemma

The researchers borrowed the trolley dilemma from philosophy to test the role testosterone plays in our moral decision making.  If you’re not familiar with the dilemma, it sees a runaway trolley about to kill five people unless it’s redirected, but doing so will result in one person being killed instead.

The team developed 24 similar dilemmas based upon real-life events to explore the trade off between utilitarian decisions (which focus on saving the most people) versus deontological decisions (which focus on not deliberately harming someone).

Previous works have suggested that higher testosterone levels lead us towards making more utilitarian decisions, so the researchers tested this by giving 100 participants a testosterone boost, whilst another 100 took a placebo.

“The study was designed to test whether testosterone directly influences moral judgments and how,” the researchers explain. “Our design also allowed us to examine three independent aspects of moral judgment, including sensitivity to consequences, sensitivity to moral norms and general preference for action or inaction.”

Interestingly, the results suggest that the testosterone fueled group didn’t make more utilitarian judgments, but rather were less likely to act in favor of the ‘greater good’.  This only seemed to occur among those who were given an artificial boost in testosterone however, as those with naturally high levels showed high levels of utilitarianism.

The authors suggest that this difference could be due to the fact that people with certain personality traits often have high levels of testosterone.  For instance, psychopaths have high levels of naturally occurring testosterone, and usually struggle with moral norms.  The thing is, it might not be the testosterone that is causing this behavior, as the results suggest when testosterone levels are artificially manipulated.

“The current work challenges some dominant hypotheses about the effects of testosterone on moral judgments,” the authors conclude. “Our findings echo the importance of distinguishing between causation and correlation in research on neuroendocrine determinants of human behavior, showing that the effects of testosterone supplements on moral judgments can be opposite to association between naturally occurring testosterone and moral judgments.”