Preference uncertainty explains choice variability in interpersonal decision-making

When expressing their preferences, people sometimes make seemingly inconsistent choices. Recently, two models have been proposed to explain this choice variability. The Preference Uncertainty model assumes that preferences change continuously, gravitating towards a particular state. The Preference Temperature model assumes that preferences are stable, but that decisions are implemented with noise. We test these models in an interpersonal decision-making task where participants can reduce their own earnings in order to increase or decrease earnings of an unknown other. Preference uncertainty, rather than noisy decisions, seem to better explain interpersonal choices. This is in line with findings on intertemporal decisions, suggesting that the same mechanism is common to different types of preferences.