Perceptual and cognitive judgments show both anchoring and repulsion

One of the most robust effects in cognitive psychology is anchoring: judgments show a bias towards previously viewed values. However, in what is essentially the same task, a perceptual illusion demonstrates the opposite effect of repulsion. Here we unite these two literatures, testing in two experiments with adults (total N=200) whether prior comparative decisions bias cognitive and perceptual judgments in opposing directions, or whether anchoring and repulsion are two domain-general biases whose co-occurrence has so far gone undetected. We find that in both perceptual and cognitive tasks anchoring and repulsion co-occur, with the direction of the bias depending on the comparison value: distant values attract judgments, while nearby values repulse judgments. As none of the leading theories for either effect account for both biases, theoretical integration is needed. As a starting point, we describe one such integration based on sampling models of cognition