Does Testosterone Impair Men's Ability to Empathize?

Hormones are complicated. Even though some "rock star" hormones become household words and seem to fit neatly in a box that explains human behavior, all too often the pop psychology reputation of a hormone is oversimplified and based on questionable scientific evidence.

For example, oxytocin has a dark side that can make people anti-social; oxytocin isn't just a cuddly, warm and fuzzy "love hormone."

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As Psychology Today blogger Christopher Badcock wrote in 2016, "Hormones such as testosterone and oxytocin can acquire an aura of positive or negative prejudice. Indeed, testosterone could be seen as the archetypical rogue hormone, with all kinds of bad behaviour routinely ascribed to it, and oxytocin as its virtuous opposite." Badcock drives home the point that "hormones are not, in fact, substances that transform good human beings into bad ones or bad ones into good ones the way magic potions do."

New research (Nadler et al., 2019) on testosterone suggests that we might need to rethink the role that this "rogue" hormone plays in making men less empathetic and the entire notion of a testosterone-driven "extreme male brain."

In the most extensive study of its kind to date, first author Amos Nadler and colleagues found no evidence of a link between increased levels of testosterone and lower levels of cognitive empathy, which the researchers describe as "the capacity to read the emotions of others."

These findings (2019) were published on September 4 in the journal Proceedings of the Royal Society B: Biological Sciences. The authors describe the significance of their findings: "With an unprecedented combined sample size, these results counter current theories and previous high-profile reports, and demonstrate that previous investigations of this topic have been statistically underpowered."

For this large-scale, double-blind, placebo-controlled experiment, 643 healthy young men received an application of testosterone gel or placebo. Soon after testosterone exposure, they were asked to perform behavioral tasks and fill out questionnaires designed to measure cognitive empathy.

"Several earlier studies have suggested a connection between testosterone and reduced cognitive empathy, but samples were very small, and it's very difficult to determine a direct link," Nadler said in a statement. "Our results unequivocally show that there is not a linear causal relation between testosterone exposure and cognitive empathy."

Nadler's 2013 dissertation was on the effects of androgens, such as testosterone, on financial decision-making. For his most recent study on testosterone and cognitive empathy, Nadler teamed up with senior author Gideon Nave of the University of Pennsylvania's Wharton School and other colleagues.

"The results are plain," Nave said in a news release. "However, it's important to note that the absence of evidence is not evidence of absence. We found that there is no evidence to support this effect of testosterone, but that doesn't rule out any possible effects. From what we know, though, it seems that if testosterone does have an influence, the effect is complex, not linear. Reality is typically not that simple."

According to Nadler and Nave, earlier investigations of a possible link between testosterone and cognitive empathy reported inconclusive findings. These studies also had limitations such as relying on correlative rather than causative evidence.

Unfortunately, dubious research on testosterone and cognitive empathy has been used to support the seemingly misguided "extreme male brain" theory of autism spectrum disorders. The "extreme male brain" hypothesis posits that autism is an exaggeration of "male" tendencies toward a cognitive style that is more systematic and less empathetic.

"The extreme male brain theory of autism has received a lot of attention," Nave said. "But if you look at the literature carefully, there is still not really strong support for it. For now, I think we have to embrace our ignorance on this."

Although the latest research suggests that testosterone does not reduce cognitive empathy, more research is needed. In my opinion, the only thing this large-scale, double-blind, placebo-controlled research proves beyond the shadow of a doubt is that the famous aphorism, "Absence of evidence is not evidence of absence," should be kept front of mind when making any "evidence-based" assumptions about the role that specific hormones play in human behavior.

In 2004, Phil Alderson wrote an editorial in the BMJ encouraging scientists to report uncertain results and to do it clearly: "We need to create a culture that is comfortable with estimating and discussing uncertainty." That said, I appreciate that Gideon Nave is openly encouraging all of us to "embrace some ignorance." In a meta way, his comfort with discussing the uncertainty of his team's research breaks some stereotypes associated with "extreme male brain" theory.