Money Shown To Boost Happiness...Temporarily

A team of economists has found that boosting the living standards of the very poor in Latin America by building them basic houses resulted in an increase in happiness, but the gain went down over time.

The theory that people have a baseline of happiness regardless of wealth seems to be corroborated in recent research. 
In one of the first studies of its kind, a team of economists set out to study the effect of improved living conditions on some of the poorest populations in Latin America. 
They worked with TECHO, a humanitarian organization which builds basic prefab houses