Pseudocontingencies in a simulated classroom.

The pseudocontingency (PC) illusion is investigated in a simulated classroom setting. Related to the notion of ecological correlations, PCs arise when the assessment of contingencies at the individual level is affected by the base-rate relations at the group level. Positive PCs arise when base rates of 2 variables are skewed in the same direction (e.g., high ability and high motivation), whereas negative PCs arise when base rates are skewed in opposite directions. Experiment 1 demonstrates that PCs between student ability and motivation are contingent on effective base-rate assessment at the group level, with a bias toward positive PCs reflecting prior expectancies. Ruling out prior expectancies, Experiment 2 yields symmetric positive and negative PCs. Experiment 3 provides evidence for PC effects on gender stereotypes. Finally, Experiment 4 extends PCs from group base rates to individual student base rates, ruling out an explanation in terms of capacity deficits or inability to assess individuating information.