A study is hitting the papers which suggests that money can be a key to happiness (if not the key) - not so much how much you have, but that you have more than your peers:
Researchers in the United States examined the "hedonic treadmill hypothesis" that suggests people are in a continual wealth race with their neighbours.I hope what is being measured is more of a cultural phenomenon than engrained human nature. (But there is evidence that the problem of 'coveting your neighbor's property' has been plaguing humans for a very long time.)
Measurements were taken of the age, the total family income and the general happiness of a group of people aged 20 to 64.
The results showed that the richer people were relative to their peers of the same age, the happier they tended to be.