A note on cue probability learning: what conditioning data reveal about cue contrast

In a probabilistic learning task with two complementary cues (C₁ and C₂) and two events (E₁ and E₂) the subject has a tendency to infer that E₂ will occur when C₂ occurs after he/she has observed that E₁ frequently goes with C₁. This phenomenon was termed cue contrast because it reflects the belief that C₂ contrasts with C₁ and should indicate E₂. Two kinds of predictions following from the notion of cue contrast were tested on response proportions from the first block of trials in four previously published experiments on cue probability learning. Of a total of 15 independent observations (eight within-group comparisons; seven between-group comparisons) 13 confirmed the predictions (sign test, p<0.005). It was concluded that cue utilization is both an inductive process based on association between cues and events and an inferential process based on contrast.