Why do people give aid?

In this weekend’s Washington Post Jacqueline Salmon asks why private aid donations occur when they do. More specifically, she looks at financial donations of Americans  (see graph) – but the questions and suggested answers are relevant to all groups and aid agencies. So what triggers that "must-give" button? She claims:

• Natural disasters beat manmade disasters (e.g. victims of hurricanes and tsunamis generally attract more donations than victims of war and other politically caused crises);
• Sudden disasters beat slow-moving crises (a sense of urgency mobilizes donors);
• TV counts (e.g. videos that allow viewers to imagine themselves at the scene make a huge difference);
• Drama and timing play an important role (e.g. the Southeast Asia Tsunmia occurred during the US holiday season);
• Ease of giving makes a big difference (i.e. over a fourth of the dollars received by the Red Cross following Katrina came in through its Web site.)
• Personal experience helps (can people relate to those affected?)
• Disaster giving doesn't supplant donations to other causes