When it comes to charity, the difference between Warren Buffett and Donald Trump may not lie in the heart but in the brain, according to new research.

The latest findings from the University of Zurich suggest that a person's predisposition for philanthropy may be related to the size of part of their brains.

Swiss scientists found a strong variation of the amount of gray matter in a brain region associated with a person's concern for others and their moral decisions, and that people who behave more altruistically possess more gray matter in this region located between the parietal and temporal lobe.

The study, published in the journal Neuron, consisted of 30 volunteers who underwent brain scans while playing a computer game in which they had to split money between themselves and anonymous partners.

Participants who made generous decisions like giving to others at the cost to themselves were found to have a larger temporoparietal junction compared to participants who made more selfish decisions.

Additionally brain scans revealed more activity in the temporoparietal junction, which rests on the right side of the brain, as each person reached their giving "limit," or the maximum they were prepared to give to others, compared to when they were making easy decisions.

Researchers said that detecting the cut-off point of how much participants were prepared to give allowed them to objectively rank the generosity of each person individually. 

"The structure of the TPJ strongly predicts an individual's setpoint for altruistic behavior, while activity in this brain region predicts an individual's acceptable cost for altruistic actions," co-author Yosuke Morishima said in a statement. "We have elucidated the relationship between the hardware and software of human altruistic behavior."

Researchers said that the findings suggest that people's tendencies don't change in a short period of time, like nice people don't become mean overnight and may explain why some people are more generous than other.

"This is the first study to link both brain anatomy and brain activation to human altruism," senior study author Ernst Fehr said in a statement. "The findings suggest that the development of altruism through appropriate training or social practices might occur through changes in the brain structure and the neural activations that we identified in our study."

While the latest findings suggest that people's "baseline level" of altruism may be hardwired into their brains, in reality decisions depends on the context and potential cost to themselves.

Researchers said that while the current computer game tests pure altruism, it is important to take into account real-world factors of being nice or generous, like people may not want to be mean or stingy to others because it will damage their reputation.

"These are exciting results for us. However, one should not jump to the conclusion that altruistic behavior is determined by biological factors alone," Fehr noted.