Door to door fundraising is hard. So how do you raise your chances of successfully getting people to contribute their share to charity? Go blonde, a new study reveals.

Researchers at the Department of Economics, University of Tennessee, Knoxville, wanted to investigate whether charity has a preference for hair color.

"This study examines how a cosmetic attribute - hair color - impacts productivity in a door-to-door fund-raising experiment," researchers wrote in the study published in the journal Economics Letters.

The study examined the amount of money people living in neighborhood blocks in Pitt County, North Carolina, were willing to contribute to the Center for Natural Hazards Mitigation Research at East Carolina University. A total of 44 solicitors went to 1,755 potential donors and elicited contributions from 522 households, according to the study.

However, for the purposes of the study, only 23 female solicitors who approached 955 households were included.

Researchers took digital photographs of each solicitor and divided the females in the study into three types: blonde, brunette, and minority females.

The results found that blonde females induced more households to contribute and elicited higher donations per contract.

The findings show that people were approximately 23 percent more likely to make a donation when solicited by a blonde woman than by her brunette counterpart. On average, blondes made $0.91 more than brunettes for each donation, with blonde averaging $2.32 and brunettes $1.41 for each donation. To determine whether hair color influences perceptions of beauty and thus charitable generosity, researchers assessed the attractiveness for each female solicitor.

"Empirical results suggest that returns to physical appearance are, on average, greater for blonde females but depend critically on characteristics of the potential donor," researchers wrote in the study.

"Further, the returns to beauty for brunette solicitors accrue largely on the extensive margin whereas the returns to beauty for blonde solicitors accrue on the intensive margin," they added.