The "hedonic treadmill" of prospect theory suggests that if people's incomes rise and stay at the new higher level, then their feelings of satisfaction also rise and stay at the new higher level.

Hedonic Treadmill

A theory suggesting that people continually seek new levels of stimulation or material goods to maintain happiness, but generally return to a stable level of happiness despite major positive or negative changes.

Prospect Theory

Prospect theory is a behavioral economic theory that describes how people choose between probabilistic alternatives that involve risk, where the probabilities of outcomes are known.