I would also postulate that the average human was happier 20000 years ago than the average human today. I also think that an average duck is happier than an average human.
> I also think that an average duck is happier than an average human.
Perhaps being able to think doesn't help much when it comes to happiness. Thinking is useful practically but it's as if you have to suppress it in order to experience happiness.
> anthropologists have found that hunter-gatherers tend to have significantly more leisure time than people in more complex societies.
https://en.wikipedia.org/wiki/Leisure#Cultural_differences