[badpun]

> In fact, despite our material success, we appear to be less happy than our predecessors.

Which predecessors? We can't really tell how a medieval peasant felt, as they didn't leave any articulate accounts. The accounts left later are generally non-representative, as people who left them were privileged (they were not illiterate). As for the more modern times, not more than 100 years ago alcoholism (strongly correlated with depression) was so rampant that the US banned alcohol sales altogether.

[CuriouslyC]

Specifically, I've seen data for post-WW2 America (at least until mid 70s) being much happier than current.

[badpun]

1. That was a period of super-high growth. Seeing positive change is one's life is one of the greatest contributors to happiness (one easy way to tap into this mechanism would be to have a terrible war that destroys everything, and then just have get their lives on track again).

2. Culture changed. In the past, people were told by society to not complain about their mental state, whereas now people are opened up almost to the point of being exhibitionistic. So, you cannot really compare reports from 50 years ago with today's numbers.