Loss aversion

In cognitive science and behavioral economics, loss aversion refers to a cognitive bias in which the same situation is perceived as worse if it is framed as a loss, rather than a gain. It should not be confused with risk aversion, which describes the rational behavior of valuing an uncertain outcome at less than its expected value.

When defined in terms of the pseudo-utility function as in cumulative prospect theory (CPT), the left-hand of the function increases much more steeply than gains, thus being more "painful" than the satisfaction from a comparable gain. Empirically, losses tend to be treated as if they were twice as large as an equivalent gain. Loss aversion was first proposed by Amos Tversky and Daniel Kahneman as an important component of prospect theory.