Detectability of Multiple Flaws

Abstract

Two experiments measured detectability, d', and two measures of criterion location for multiple flaws presented separately versus mixed. In the first experiment, the different flaws were the same in type but differed in magnitude; in the second experiment the flaws were of different types. In Experiment 1 there was no difference in d' for either magnitude of flaw as a result of the separate versus mixed conditions, (i.e., each magnitude of flaw had its own d' in both separate and mixed conditions). However, in Experiment 2 all flaws had lower d's in the mixed condition than when each was presented alone. In neither experiment was there any difference in average criterion location between the separate and mixed conditions, nor did individual criterion locations for easy versus hard flaws presented separately differ in Experiment 1. In Experiment 2 there was a difference in individual criterion locations for the different flaws presented separately, such that for the hardest to detect flaw, false rejection error rate was lower and miss rate higher than for either of the two flaws with larger d's.