THE EFFECT OF THE FREQUENCY OF JUDGMENT AND THE TYPE OF TRIALS ON COVARIATION LEARNING

This study showed that accuracy of the estimated relationship between a fictitious symptom and a disease depends on the interaction between the frequency of judgment and the last trial type. This effect appeare d both in positive and zero contingencies (Experiment 1), and judgment s were less accurate as frequency increased (Experiment 2). The effect can be explained neither by interference of previous judgments or mem ory demands (Experiment 3), nor by the perceptual characteristics of t he stimuli (Experiments 4 and 5), and instructions intended to alter p rocessing strategies do not produce any reliable effect. The interacti on between frequency and trial type on covariation judgment is not pre dicted by any model (either statistical or associative) currently used to explain performance in covariation detection. The authors propose a belief-revision model to explain this effect as an important respons e mode variable on covariation learning.