Easterlin, Richard A. “Income and happiness: Towards a unified theory.” The economic journal 111.473 (2001): 465-484.
Material aspirations are initially fairly similar among income groups; consequently more income brings greater happiness. Over the life cycle, however, aspirations grow along with income, and undercut the favourable effect of income growth on happiness, although the cross-sectional happiness-income difference persists. People think they were less happy in the past and will be happier in the future, because they project current aspirations to be the same throughout the life cycle, while income grows. But since aspirations actually grow along with income, experienced happiness is systematically different from projected happiness. Consequently, choices turn out to be based on false expectations.