Narcissistic tendencies moderate the association between testosterone levels and generosity in men

New research provides evidence that narcissism moderates the relationship between testosterone and generosity in men. The study, published in Hormones and Behavior, found that the most generous men tended to be low in endogenous testosterone and simultaneously low in narcissism. Unexpectedly, however, the researchers also found that heightened testosterone levels in combination with heightened narcissism was a significant positive predictor of generosity.

“Physiological changes constantly occurring in living organisms are interconnected with behavioral outcomes in many intricate and fascinating ways,” said co-author Magdalena Ziemiańska, a PhD student at the Polish Academy of Sciences. “We were curious to examine how a normal (i.e. baseline) level of testosterone is linked to social behavior.”

“A simple economic game was applied, in which the participants’ task was to divide points between themselves and a stranger,” Ziemiańska explained. “We wanted to check if a popular belief, derived from animal studies, that high testosterone level is connected with competitive, antisocial behaviors is true in humans.”

“We also wanted to find out how narcissism interacts with testosterone levels and how these interactions are linked to behavior,” added first author Anna Z. Czarna, an associate professor at Jagiellonian University. “Narcissism and testosterone are associated with similar behavioral outcomes, such as aggression, competitiveness and striving for status, to the extent that narcissism is considered a stereotypically masculine trait.”

“This similarity was likely the reason why some scholars (such as Nicholas Holtzman and Michael Strube) speculated that high male narcissists might simply have higher baseline testosterone levels,” Czarna said. “This idea has not been consistently backed up by research so far. Instead, more complex relations between narcissism and testosterone emerged. We aimed to contribute to further explanation of these mysteries.”

The researchers conducted two studies with 151 male participants from Poland. The participants first completed a validated measure of narcissistic personality traits. They also completed a scientific assessment known as the Triple Dominance Measure, which is used to assess “the weight people assign to their own versus others’ outcomes in interdependent situations.”

In the Triple Dominance Measure, participants are asked to imagine that they have been randomly paired with another person, who is a stranger. They are then presented with a series of nine resource allocation decisions.

Based on their responses, “each participant can be classified as prosocial, competitive, or individualist. Prosocials maximize outcomes for both themselves and others (i. e., cooperation) and minimize differences between outcomes for themselves and others (i.e., equality); individualists maximize their own outcomes with little or no regard for others’ outcomes; and competitors maximize their own outcomes relative to others’ outcomes, seeking relative advantage over others,” the researchers explained.

Next, the participants visited the laboratory and provided two saliva samples — spaced 20 minutes apart — which were used to measure testosterone levels.

As expected, the researchers found that narcissism moderated the association between testosterone and resource allocation decisions. The findings indicate that “high vs. low narcissism affects the relationship between testosterone level and generosity in men,” Ziemiańska explained.

However, not all the findings were in line with their hypotheses. The researchers had predicted that higher testosterone would be negatively associated with the amount of resources shared with others, and that this association would be amplified by heightened narcissistic tendencies. But a more complicated relationship emerged.

“In low narcissists, testosterone was linked to less prosocial behavior,” Ziemiańska told PsyPost. But “in high narcissists, testosterone was linked to more prosocial choices.”

“Altogether, the pattern of results was a bit counterintuitive,” she said. “The two different factors i.e. psychological trait narcissism and the level of hormone testosterone influenced social behavior in a rather unexpected fashion. As mentioned before, popular beliefs are that high testosterone levels, as well as high narcissism, are linked to competitive, antisocial behavior (even explicit aggression).”

“This is why we were surprised to discover that, contrary to these popular beliefs, endogenous testosterone was associated with lower generosity among less narcissistic — thus more trustful, less cynical, more habitually generous, and less selfish — men,” Ziemiańska explained.

The findings might also have some practical implications.

“One (perhaps somewhat funny) takeaway message from our study would be: if you are choosing a date, beware of highly narcissistic men who are simultaneously low on baseline testosterone – in our studies, they were the least generous (and most selfish) in their decisions,” Czarna added. “They shared the least resources with others. So, when going on a date with one of them – prepare to pick up the bill. Meanwhile, men who were low on both narcissism and testosterone were highly generous.”

“Looking at our results from yet another perspective, high baseline testosterone worked a bit like an equalizer,” the researcher explained. “Men with high testosterone behaved similarly, they split their resources in similar and moderately generous ways, regardless of their narcissism levels. Men low on baseline testosterone differed highly in their behavior, depending on their personalities: those highly narcissistic were significantly less generous than those with low narcissism levels.”

The findings shed new light on how testosterone might interact with personality to influence behavior. But the researchers noted that scientists are still in the early stages of untangling the complex relationships between psychological traits and biological processes.

“Our study was one of the few first studies that looked at the interplay between personality and hormonal levels,” Czarna explained. “There is still a lot to do. These relationships are usually complex, not straightforward. Multiple other personality traits as well as multiple other situational factors still await investigation in the context of their interactions with hormones.”

“Future studies involving larger groups of participants could measure implicit motives and situational factors (i.e., opportunities to increase status or challenges and threats to social standing) and assess their interactive influence on testosterone reactivity and behavioral outcomes,” Czarna said. “Such studies promise to disentangle the effects of motives, situations, traits (i.e., narcissism), and testosterone.”

The study, “Narcissism moderates the association between basal testosterone and generosity in men“, was authored by Anna Z. Czarna, Magdalena Ziemiańska, Piotr Pawlicki, Justin M. Carre, and Constantine Sedikides.