Donors to charities have been found to exhibit a higher level of virtuous behavior than the rest of the general population.  A University of Chicago General Social Survey found that donors who give to charity at least once a year also have these characteristics:
 

15% more likely than non-donors to give directions to a stranger
17% more likely to give up their place in line
22% more likely to give up a seat on the bus
46% more likely to give food or money to a homeless person
125% more likely to give blood