Researchers reporting in Current Biology found that the human instinct to share is very old, and may be tied to the mimicking behaviour.
New evidence gathered from a six year study of the Hadza hunter-gather people in Tanzania shows that people are generally willing to share, thought that doesn’t mean they always do.
An individual deciding to share depends not on the individual, but rather the group they live with at the time, demonstrating that herd mentality has a lot to do with generosity.
"We found that year after year, willingness to share with others clustered within residence groups or what we call ‘camps'," says the lead author of the study, Coren Apicella of the University of Pennsylvania.
People were living with other people who were similar to them in levels of generosity.
Kristopher Smith, another author said:
We also found individual willingness to share changed from year to year to match their current campmates and found no evidence that people preferred living with more cooperative people.
Those trends remained consistent even as the Hadza people changed campmates every few months.
Ibrahim Mabulla, one of the researchers on the project revealed that the Hadza are "one of the last populations left on the planet who live a similar lifestyle to how our ancestors lived for million years".
Researchers visited 56 camps in Tanzania over the course of six years and looked at some 400 adults and the way they responded after being asked to play a game. The game is normally played by asking people to decide whether to share money with a group or keep it just for themselves. However, researchers asked them to consider sharing straws of honey, their favourite food.
Results showed that those honey straws that were given to the group got tripled, and this evidence suggests individuals behaved differently over time and became more, or less generous depending on the group they were with.