Women are more generous than men and it may be down to how our brains react to chemicals, new research has claimed.

Scientists from the the University of Zurich say that dopamine – a neurotransmitter which helps communicate pleasure and reward and is partly responsible for that “feelgood” rush you get when you are showered with praise – may have a role to play when it comes to altruism.

The team carried out a series of tests on a group of 56 who were randomly given a placebo or amisulpride – a drug that prevents dopamine from carrying out its function in the brain.

The test subjects were then presented with various hypothetical scenarios asking them what they would do when given a certain amount of cash.

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The experiment was later repeated with the alternative pill.

When taking the placebo, 51% of the time women chose to share the money, compared to 40% of men, but after taking amisulpride, women were less keen to give, with 45% of them agreeing to split the cash.

On the other hand, amisulpride made men slightly more prosocial, with 44% agreeing to share their bounty.

In another experiment, the team looked at brain imaging data from 40 people who made decisions on whether to share or keep the money.

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It showed that the striatum – which is located in the middle of the brain and is responsible for the assessment of reward – was more strongly activated in female brains during prosocial decisions.

“These results demonstrate that the brains of women and men also process generosity differently at the pharmacological level,” study author Alexander Soutschek said.

He added: “The reward and learning systems in our brains work in close cooperation.

“Empirical studies show that girls are rewarded with praise for prosocial behaviour, implying that their reward systems learn to expect a reward for helping behaviour instead of selfish behaviour.”

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However, Soutschek warns against assuming that there may be an evolutionary origin to why women appear more generous.

“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,” he said.

While the study sample is small, Soutschek believes the findings could play a role in further brain research, saying: “Future studies need to take into account gender differences more seriously.”

This research is published in Nature Human Behaviour.