Estimates Of Conditional Probabilities Research Articles

Bias in estimates of conditional probabilities and betting behavior as a function of relative frequency and validity of cues in a Cue-Probability Learning task

In a cue-probability learning task with two nonmetric cues and events effects of distribution of cue probabilities, P( C j ), and cue validities, P( E i / C j ), on estimates of conditional probabilities and betting behavior were studied. The design was factorial with 3 levels of P( C j ) and 2 levels of both P( E i / C j ). Immediately after the learning session subjects made a bet on the outcome of either of the cues and thereafter estimated some of the probabilities in the task. The hypothesis that the validity of the less frequent cue would be underestimated was confirmed. An opposite effect of overestimating the validity of the more frequent cue was also observed. Parallel results were obtained for betting behavior. There was a general tendency of choosing the more frequent cue irrespective of cue validity. This tendency to disregard valid but rate information merits attention, since it promotes suboptimal decisions.

Estimates of conditional probabilities of confirming versus disconfirming events as a function of inference situation and prior evidence.

Estimates of conditional probabilities of confirming versus disconfirming events as a function of inference situation and prior evidence.

The logical consistency of person perception

Ss made both conditional and unconditional probability estimates concerning persons (Negro and white) and person-attributes. When these estimates were evaluated in terms of the axioms of probability theory, it was found that Ss tended toward logical consistency but that consistency varied according to the characteristics of the stimulus person (Negro or white). Furthermore, the differential effects of Negro-white stimulus characteristics upon consistency were greater for white than for Negro Ss.