A meta-analysis examines the progress scientific psychology has made in strengthening its practices and results.

The Harvard study, like a lot of other happiness research, posed that same question of cause and effect that had bedeviled psychology for so long: It was hard to know, for example, if happy ...

But the study authors ... presented by the paper. The research team that authored the new paper say the observations have reached the three-sigma level of significance, or a 0.3% probability ...