Gimme (and 'em) More

What are the benefits of participating in a clinical trial? Ethicists have tended to divide benefits into three categories: direct, collateral, and aspirational. The first involves medical benefits flowing from the study intervention; the second, from increased medical monitoring. The third refers to the benefits that flow to society from the knowledge gained.

But are aspirational benefits external to the individual? That is, do they flow to society exclusively, or do they accrue to individuals who participate in studies– a sort of satisfaction that comes from having "given back" to society?

This Sunday's NYTimes featured an article by David Leonhardt, titled "What Makes People Give?"  The article describes some emerging findings from a branch of economics concerned with philanthropic behavior. One area of bioethics that calls out for further empirical and analytic research is what might be called corporal philanthropy. What makes people give their bodies? And to what extent is it ethical to harness these motivations, or perhaps even to prime them, in order to induce them to give more?