In a novel double blind experiment designed to identify whether differences in our brain's chemistry could help explain generosity, researchers from the University of Zurich restricted dopamine receptors in a group of volunteers and watched as they were given a sum of money.
Dopamine is a neurotransmitter that performs a bunch of different tasks in the brain, one of which helps communicate pleasure and reward. That 'feel good' rush you get when you receive praise or achieve a goal is in part mediated by this chemical.
The researchers based their research on a sample of 55 participants – 27 identifying as female, 28 as male.
The volunteers were randomly sorted into two groups before being dosed with either a dopamine blocker called amisulpride or a placebo.
They were then given two tasks. In the first, each was given a choice between getting a handful of Swiss francs to keep, or a smaller reward that was shared with a friend in the group or somebody who was more of a stranger.
The second task served as a control, where the participant was offered a choice between a small reward now and a bigger reward if they waited 90 days.
Once evaluated, the two groups were swapped to receive the other pill and be tested again.
The results weren't mindblowing, but they were determined to be significant.
When taking the placebo, women in the study chose to share 51 percent of the time. Men, on the other hand, did this on just 40 percent of occasions.
With the dopamine blocker, women offered to split their prize just 45 percent of the time. Men actually became slightly more prosocial without the dopamine at 44 percent.
The study indicates that, down a gender division of male or female participants, there could be differences in the neurotransmitter rush that nudges them to be a little more caring and sharing.
Beyond that statistical variation, it's currently all speculation. It's not clear if this difference could emerge from variations in our chromosomes, or if it's a learned behaviour shaped by decades of social conditioning.
Critically, a group of 55 is also a fairly small sample size, and the differences – while interesting – weren't exactly overwhelming.
Adding to this, as cognitive neuroscientist Gina Rippon from Aston University told Nicola Davis at The Guardian, the data was pooled from two different groups of participants performing slightly different tasks, introducing room for error.
All of that aside, the conclusions raise some fascinating questions on the limits of decision making and the influence of gender. There's just more work to be done to explore what this result could really mean.
Throughout history, scientists have debated the characteristics that separate men and women and wondered how much is nature – and deeply embedded – and how much is nurture, subject to change.
Experiments like this one offer tools for studying the neurochemistry behind pro and antisocial behaviours, potentially helping us better understand the subtle interactions of genetics, cultural expectations, and anatomy.
Who knows, it might turn out men and women are both from Earth after all.
This research was published in Nature Human Behaviour.
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