Women are more likely than men to opt out of giving a charitable donation, a group of economists including an Indian-origin student have found.

A new field experiment conducted by scholars at the University of Chicago and University of California, Berkeley, tested people's motivations to give, whether they responded to social pressure or from an attitude of altruism.

In the study, researchers visited neighbourhoods to raise money for a local children's hospital and an out-of-state environmental organization.

In one part of the study, visits were unannounced. In two other parts of the study, people received fliers-either announcing the solicitation the following day or giving people an opportunity to opt-out of the request for funds.

"The simple flier lowers the share of people answering the door, relative to the people who did not have warning of the visit, but it does not affect the share of people giving," John List, a UChicago economist and expert of philanthropy, the Homer J. Livingston Professor in Economics, said.

"The opt-out option lowers both the share of people answering the door and the share of individuals giving," he said. The drop in women's giving largely drives this change, List explained.

About three percent of women and men gave money when the visit was unannounced. When allowed to opt-out, men's giving dropped slightly, while women's giving fell to about half of the level of previous giving.

When the scholars looked over other data in the study to determine gender-specific altruism distributions, they found that women were more likely at the margin of giving to a charitable cause, and therefore more likely to opt-out if they had a chance.

Other authors of the study are Stefano DellaVigna and Ulrike Malmendier, both professors of economics at the University of California, Berkeley; and Gautam Rao, a graduate student in economics at the University of California, Berkeley.