Lead researcher Ioannis Evangelidis and Bram Van den Bergh of the Rotterdam School of Management at Erasmus University in the Netherlands, examined humanitarian relief data for natural disasters occurring from 2000-10. As they expected, they found that the number of fatalities predicted the probability of donation, as well as the amount donated, by private donors in various disasters.
Their model estimated that about $9,300 was donated per person killed in a given disaster. However, the number of people affected in the disasters, on the other hand, appeared to have no influence on the amount donated to relief efforts.
Evangelidis and Van den Bergh said donors were more likely to pay attention to a death toll when deciding how much to give because the term "affected" is ambiguous. In many cases, though, fatalities don't correlate with the number of actual people in need.
To find a way to combat this donation bias, the researchers brought participants into the laboratory and presented them with several scenarios, involving various types of disasters and different numbers of people killed and affected.
Overall, participants allocated more money when a disaster resulted in a high death toll -- even when the number of people affected was low -- mirroring the data from the real natural disasters, the study said.
"Above all, attention should be diverted from the number of fatalities to the number of survivors in need," Evangelidis and Van den Bergh concluded. "We are optimistic that these insights will enhance aid to victims of future disasters."
The findings were published in the journal Psychological Science.