A recent performance of Anne Nelson's moving 9/11 play The Guys introduced me to the concept of the "square rooter"—people on a team who are only out for themselves (when your formula is "me times me," your square root is me). Square rooters may be brave and energetic and effective, but there's something missing there ("the last temptation is the greatest treason: to do the right deed for the wrong reason"). And now this long-term look at the effects of volunteering claims this moral deficit has a physiological cost: It found that people who volunteer time to serve others tended to live longer—but only if their motivation was selfless.

Selfish motives to volunteer (to get into a good college, to learn how to use InDesign, to make business contacts, to have a place to store your boat, to meet chicks), don't confer the same benefits, apparently. People with self-serving motives died at the same rate as people who didn't volunteer at all, said the paper, published in this month's Health Psychology. (It's behind the usual obnoxious paywall, but you can read the whole thing in this pdf of a late draft.)

Sara Konrath and her co-authors used a trove of data from the Wisconsin Longitudinal Study, which has tracked the health and habits (and, of course, occasional deaths) of 10,317 Wisconsinites since they graduated from high school in 1957.

In 2004, the still-living participants had been asked whether they'd volunteered their time and effort over the previous decade, and, if yes, how heavily they had participated in those activities. They were also asked to choose among ten possible motives for their generosity. Four of these involved what Konrath et al. call "other-oriented motives" (for example, "I feel it is important to help others" and "I feel compassion toward people in need"). The six others were "self-oriented" (for instance, "volunteering makes me feel better about myself" and "I can explore my own strengths").

The researchers then performed a logistic-regression analysis to see if people's motive for volunteering had any effect on their risk of death. This involved not just cross-tabulating motives and deaths but also paring away the effects of age, gender, marital status, income, religion, and overall health, both physical and psychic. (It must be a pleasure to work with such a deep and thorough data set—unlike a typical psych experiment, which uses a motley crew of undergrads available that semester, the Wisconsin data apparently can answer any health-related question about people, going back decades.)

A total of 3,376 people fit all these criteria—ie, they had volunteered (or wanted to) and they'd answered the 2004 questionnaire about motives. It turned out 98 of them had died by 2008. According to the statistical analysis, the authors write, selfless volunteers were less likely to be among the dead, while selfish volunteers were more likely to be.

Why should motives matter so much? There's no hard evidence yet but Konrath et al. speculate that the reason has to do with stress: Volunteers often have to cope with too little time, too few resources, too many hard cases and too much heartbreak. Perhaps selflessness protects against that kind of stress in a way the selfishness doesn't. The test, I suppose, would be to use the group of people in the Wisconsin data who said they wanted to volunteer but had not actually done so. If it turns out that wanting to be unselfish increases longevity even in the absence of any concrete action, the case for this paper's hypothesis looks stronger.

If the idea holds up, it suggests that volunteer organizations could protect themselves from burnout by running their operations with an eye on motives. For example, the authors write, selfish volunteers may need more help to avoid burnout, for instance. And if organizations want to have more of the less troublesome selfless volunteers, then they may want to recruit by emphasizing aid to others—rather than encouraging potential volunteers to see their service as a quid-pro-quo exchange.

Konrath S, Fuhrel-Forbis A, Lou A, & Brown S (2011). Motives for volunteering are associated with mortality risk in older adults. Health Psychology : official journal of the Division of Health Psychology, American Psychological Association PMID: 21842999