A very interesting article in Newsweek on generosity:
People are more willing to help a single individual than many. In an experiment, one group was given general information about the need for donations, including statements like "Food shortages in Malawi are affecting more than 3 million children." A second group was shown the photo of a 7-year-old Malian girl named Rokia, and told that she is desperately poor, and that "her life will be changed for the better by your gift." People in the second group gave more.