1) Rich people are happier than poor people.All of which should come as no surprise to anyone, without the benefit of "happiness research." Regarding which, I agree with Arnold Kling, who says:
2) Richer countries are happier than poorer countries.
3) As countries get richer, they tend to get happier.
My view is that happiness research implies Nothing. Zero. Zilch. Nada. I believe that you do not learn about economic behavior by watching what people say in response to a survey.You learn about economic behavior by watching what people actually do.
And...you consult your "priors." It is axiomatic that individuals prefer more to less; that is, more income yields more satisfaction because it affords access to goods and services of greater variety and higher quality. Moreover, income and the wealth that flows from it are valued for their own sake by most individuals. (That they might be valued because they enable philanthropic endeavors is a case in point.)
It is reasonable to conclude, therefore, that the "law" of diminishing marginal utility, which may apply to particular goods and services, does not generally apply to income or wealth in the aggregate. But, in any event, given that Wolfers's first conclusion is self-evidently true, the second and third conclusions follow. And they follow logically, not from "happiness research."