抄録
The present study was performed to examine "conjunction fallacy phenomenon" in the probability judgment of a compound event in order to investigate how each constituent of compound event has an effect on the process of generating the probability estimate of compound event. Each problem of probability judgment included two constituent events (a representative and an unrepresentative event), one compound event and two personality sketches whose character show a remarkable contrast. One of two personality sketches was constructed to be representative of one of constituents of compound event and unrepresentative of the other. Subjects evaluated the probability of identical compound event for two personality sketches. Multiple-regression analyses were performed on probability estimate, regarding the probability estimates of constituent event as independent variables and the probability estimates of compound event as dependent variable. The result indicated that the weight given to the two constituents in the compound event was quite different. This result was interpreted as suggesting that representative and unrepresentative constituent had unequal effect on generating the probability estimates of compound event. This unequal contribution to generate the probability estimates of compound event was discussed in termes of Hampton's composite prototype theory.
