In my previous blog entry ("Does Happiness Have a Cost?"), I discussed some studies showing that experimentally-induced happiness can have a cost. I cautioned that state research is not the same as trait research. That is, experimentally-induced emotions (like happiness) may not have the same consequences as habitual dispositions associated with these emotions (like life satisfaction).

But sometimes state research and trait research point to the same conclusion. An important paper by Shigehiro Oishi, Ed Diener, and Richard Lucas, published in 2007 in Perspectives on Psychological Science, showed that dispositional happiness (rendered as life satisfaction) can have costs. These costs are not across-the-board; they depend on the specific outcome on focus.

These researchers looked at cross-sectional and longitudinal data from several large samples in which adult respondents had completed a life satisfaction measure and for whom other information about "success" in a variety of domains was available. The researchers were interested in how success varied as a function of life satisfaction.

Important finding one: Happy (satisfied) people were more successful than unhappy (dissatisfied) people regardless of outcome.

Important finding two: When the comparison was between the most satisfied and the merely satisfied, the outcome mattered. For success at close relationships, the extremely happy did better than the somewhat less happy. But for success at school, work, and political participation, the happiest people did not do as well as those who reported slightly less satisfaction. (But please remember important finding one.)

The researchers concluded "Once people are moderately happy, the most effective level of happiness appears to depend on the specific outcomes used to define success, as well as the resources that are available."

Okay. There are apparently circumstances in which one can be too happy. These findings admit to different interpretations. In some cases, the data were all obtained at the same time from respondents, leaving unanswered legitimate questions about what comes first, the reported satisfaction or the success. In other cases, though, these patterns held across time, strengthening the conclusion that satisfaction actually results in given outcomes. In these cases, perhaps the moderately happy among us are hungrier than the fully satisfied--more motivated--and thus put more effort into achievement domains.

Or perhaps considerable happiness more readily translates itself into good relationships than into good grades or a high income, if only because happiness is contagious and thus attractive to others.

Or it could simply be that there are but 24 hours in a day, resulting in necessary tradeoffs in what anyone can achieve. As Ed Diener reminded me when I spoke to him about this possibility: "Newton got so much physics done because he did not like social interaction."

We all make choices, or they are made for us. As a college student, I worked like a dog and had nothing that resembled a social life. My good grades opened doors for me not otherwise ajar. I walked through them, if not happily then at least purposefully. But thirty years later, as a tenured professor at a top university, I now have all the dog biscuits I could possibly want. And I also have wonderful friends. Maybe we can have it all--just not at the same time. Bow wow.