My brother and I are polar opposites. He has always been the social butterfly, the one that everybody knows. He thrives off of going out with his friends, making decent money at his job, and spending a pretty penny on luxuries for himself. I, on the other hand, have always laid low compared to him and enjoyed another kind of lifestyle: while I love and value my friendships like he does, we don’t quite see eye-to-eye on the monetary end of things. Instead of rewarding myself, I like to give it back to the world. I prefer to donate it, invest it, help others with it.

We’ve always laughed about our total opposite personalities and never quite understood how we could be related. But a new study “The dopaminergic reward system underpins gender differences in social preferences” conducted by researchers from the University of Zurich sheds some light on why our values are so different and explains that this difference is, in fact, normal. They were able to show that females and males process prosocial (or voluntary behavior that benefits others) and selfish behavior differently—prosocial behavior activates a stronger reward signal in women, while selfish behavior triggers a stronger reward signal in men.

Previous behavioral experimentation has shown that women share money more generously than men. This enticed the team of neuroscientists and led them to take a look at how our brains are activated when decisions of the like are made. In the first experiment, they found that the striatum—a critical component of the reward system located in the middle of the brain—was more strongly activated in female brains when they made prosocial decisions versus selfish decisions. And quite contrarily, a stronger activation of the reward system in the male brains came with making selfish decisions.

In the second experiment, the researchers introduced medication into the equation. They found that when medicated, the women actually behaved more selfishly and the men more prosocial, which came as a surprise to the team. “These results demonstrate that the brains of women and men also process generosity differently at the pharmacological level,” explains lead author Alexander Soutschek. He goes on to say that gender differences are important factors and need to be taken more seriously in future studies.

While this difference in reward stimulation appears to be biological, Soutschek says that we shouldn’t be so quick to assume they’re of evolutionary origin. “The reward and learning systems in our brains work in close cooperation. Empirical studies show that girls are rewarded with praise for prosocial behavior, implying that their reward systems learn to expect a reward for helping behavior instead of selfish behavior,” he says. “With this in mind, the gender differences that we observed in our studies could best be attributed to the different cultural expectations placed on men and women.”

I’ve spent years trying to convince my brother into adopting my more generous ways, and he continues to tell me that I’m just too nice. And while this research explains that our different cultural expectations are to blame, which helps us better understand why neither of us have budged, I haven’t given up just yet—even with the wiring of our brains standing in my way.

Source: University of Zurich “Female Brain Reacts More Strongly to Prosocial Behavior Than Male Brain.” NeuroscienceNews. NeuroscienceNews, 9 October 2019.

Original Research: Abstract for “The dopaminergic reward system underpins gender differences in social preferences” by Alexander Soutschek, Christopher J. Burke, Anjali Raja Beharelle, Robert Schreiber, Susanna C. Weber, Iliana I. Karipidis, Jolien ten Velden, Bernd Weber, Helene Haker, Tobias Kalenscher & Philippe N. Tobler in Nature Human Behavior. Published online October 9 2019 doi:10.1038/s41562-017-0226-y