One of my favorite researchers has done it again. Dr. Robert Biswas-Diener renowned author of many books in the field of positive psychology published some great research on giving to charity and increased personal happiness.
The link to the actual study can be found at: http://www.hbs.edu/research/pdf/11-038.pdf
The research compared people in a rich and a poor country (Canada and Uganda). Participants were asked to think about the last time they spent the equivalent of 20 dollars on either themselves or on another person. Whether rich or poor, participants reported more happiness when they remembered spending money on others. Dr. Biswas-Diener and his colleagues surmised that humans are hard-wired for generosity.
This suggests that the happiness we feel when we lend support or donate money is part of the natural psychological reward system for looking after others.
Dr. Biswas-Diener can be reached at http://www.intentionalhappiness.com/