Raise your hand if you have ever volunteered for an organization. I’d bet most of you at one time or another have volunteered for a cause you believed in. Maybe you helped collect canned goods for a community kitchen, or tutored a student, or sold Girl Scout cookies, or ran a 5K race for a good cause.

We all have different causes we believe in and motivations for volunteering. But I have trouble grasping the motivation for some people’s volunteer choices.

A few years ago, NASA advertised for volunteers for a study on how space flight affects healthy bodies. They recruited fit, healthy volunteers who matched the general physical profile of their astronauts. Then they asked these volunteers to spend 15 weeks in a hospital bed so they could measure how this bed-rest position affects human f…