We generally assume people are altruistic - they like to see the poor being helped, for example - but the first best is always for the poor to be helped, but for me to keep my money. In general for public goods we call this the free-rider problem, since I can get just as much OPB whether I contribute or not there is no reason for me to contribute. Yet I, and many others, do. Well, perhaps it is because we actually get satisfaction from the act itself - economists call this the 'warm-glow' motive - in which case we are actually making ourselves happier by contributing.
But is it all true this way that economists think about these decisions? Well, the emerging field of 'neuro-economics' hopes to better understand such things by watching brain function of people in the process of making such decision through the use of functional MRI. One such person working in this field is Bill Harbaugh of the U of Oregon, who has looked at charitable giving and has found:
Consistent with pure altruism, we find that even mandatory, tax-like transfers to a charity elicit neural activity in areas linked to reward processing. Moreover, neural responses to the charity's financial gains predict voluntary giving. However, consistent with warm glow, neural activity further increases when people make transfers voluntarily. Both pure altruism and warm-glow motives appear to determine the hedonic consequences of financial transfers to the public good.
So, it appears that it is a general part of our preferences: we may be hard wired to get pleasure from charitable acts.
Now there are a few caveats: functional MRI is looking only at one type of brain function and is pretty crude relative to the sophistication of the brain. So, just because we see stimulus in certain areas of the brain it is not yet clear that we can generalize this into preferences the way that economists think of them. However, that said, the results suggest that you are happier if you give.
Given this result we might want to ask: what is altruism? Or, it is really altruism if we get pure pleasure from it?
Either way, OPB is waiting for your call...