Unless it's been superceded in the last decade, the best study I know of on
the causes of happiness (or at least what factors happiness correlates
with) is Michael Argyll's The Psychology of Happiness. I bought this in
England in the '80s, so it may not be available in the U.S.
Max
http://www.maxmore.com
Max More, Ph.D.
<more@extropy.org> or <max@maxmore.com>
Consulting services on the impact of advanced technologies
President, Extropy Institute:
exi-info@extropy.org, http://www.extropy.org