Measures of need-based justice that have been proposed lately rely on a single dimension of need that is taken into account. This is shown to be problematic since humans experience different kinds of need that appear to be incommensurable.

Imagine that only the state can meet the need for housing but decides not to do so. Unsurprisingly, participants in a vignette experiment deem this scenario unjust. Hence, justice ratings increase when the living situation improves. To a lesser extent, this also holds beyond the need threshold, understood as the minimum amount necessary for a decent life. Surprisingly, however, the justice evaluation function is highly convex below this point. The resulting S-shaped curve is akin to the value function in prospect (...) theory, with the need threshold providing the point of reference and inflection. A control treatment without needs-information supports this interpretation. Needs-information furthermore compresses the perceived injustice of arbitrary inequality. As in prospect theory, such reference dependency suggests biases in judgment and decision making. A consequence may be that the lot of the poorest in society does not receive the attention it would otherwise get. (shrink)