Probability processing and diagnostic search: 20 alternatives, 500 trials

Ss’ capabilities for processing probability information in performing a diagnostic search task similar to troubleshooting is explored. Six Ss searched (queried) among 20 components in a series circuit to isolate a single component failure per trial. Failures were generated according to 10 alternative probability-of-component-failure distributions (D), each with N = 500. Prior to performing their search on a trial, Ss predicted the failure for that trial. Of primary interest was the influence of varying D on predictions and search performance. Results indicate that: (1) distributions of predictions tend to match actual D in shape and location but exhibit certain characteristics; (2) probability of correct prediction is low and is influenced by D; (3) search strategies are suboptimal but “logical” and to some extent predictable; and (4) in some instances, search strategy appears to be related to predictions.