One of the most important, and maybe controversial, conclusions from happiness research in psychology is the notion of a "set point." This is the idea that we inherit a level of happiness that determines around 50% of how happy we'll be. While I cannot dispute the validity of the studies that support this claim, I'm skeptical of the conclusions and meaning we ascribe to it.

Sonja Lyubomirsky, in The How of Happiness, makes a strong case for the set point theory early on in the book. She cites a handful of studies, and the most compelling ones are about twins separated-at-birth who remain nearly equal in happiness.

But what does this set point mean? What is the set point made of? A happiness set point is most closely related to the concept of homeostasis, which, in the case of body temperature, means our body has a tendency to reach a stable equilibrium. However, homeostasis always requires some sort of regulators. If we have a happiness set point, what's regulating it? Is it our inherited balance of neurotransmitters? Or is it our inherited temperament? For example, my mom is anxious and fidgety, and I seem to have inherited that.

But what if there aren't any internal regulators? What if we have inherited behavioral tendencies that keep our happiness at certain levels. For example, I inherited a propensity for risk-taking from both my parents, and as a result, I do better in America, the "land of opportunity," and am therefore happier. Or let's say I inherited a weakness in making judgments of other people. As a result, I always end up in unhappy relationships.

If this were the case, the research data would appear the same. We'd still have happiness set points, but we wouldn't know whether they were internally caused, like our internal body temperature, or externally caused.

Reptiles don't have regulated internal body temperatures. They have to go in and out of sun in order to maintain a temperature. By doing so, they can still exhibit a body temperature set point. We could genetically modify the reptile to spend more time in the sun and therefore observe a higher body temperature.

Sonja's right, there are definitely set points. We all know somebody that always seems happy no matter what. But is his happiness really that durable? What if this Mr. Pleasant got into an abusive relationship? When I discuss this hypothetically with my friends, we come to the same conclusion that, "Well, he wouldn't get into that situation in the first place."