This paper provides a theoretical rationale for three experimental results of Prospect Theory: risk preferences are over gains and losses, loss aversion, and diminishing sensitivity. We consider a (boundedly rational) decision maker who does not find her new optimal consumption bundle with certainty when she is faced with a new income level. This alters her indirect utility function and makes her more risk averse at her current reference income level and less risk averse for a range of incomes below her reference income level.