Key to happiness, maybe not. But money appears to be useful for more than just gas (or contributing to your public radio station). New Scientist reports:
Simply thinking about words associated with money seems to makes us more self-reliant and less inclined to help others. And it gets weirder: just handling cash can take the sting out of social rejection and even diminish physical pain.... Put bluntly, it looks as if money is acting as a surrogate friend. Could that explain why some people focus on extrinsic aspirations at the expense of real social relationships?
The question they eventually get to: can money be addictive? No definitive answers are given, rather an argument that economists' models can't be taken seriously unless they figure in people's sometimes irrational desire for money.