Long-term memory for unfamiliar voices.

From a sample of young male Californians, ten speakers were selected whose voices were approximately normally distributed with respect to the "easy-to-remember" versus "hard-to-remember" judgments of a group of raters. A separate group of listeners each heard one of the voices, and, after delays of 1, 2, or 4 weeks, tried to identify the voice they had heard, using an open-set, independent-judgment task. Distributions of the results did not differ from the distributions expected under the hypothesis of independent judgments. For both "heard previously" and "not heard previously" responses, there was a trend toward increasing accuracy as a function of increasing listener certainty. Overall, heard previously responses were less accurate than not heard previously responses. For heard previously responses, there was a trend toward decreasing accuracy as a function of delay between hearing a voice and trying to identify it. Information-theoretic analysis showed loss of information as a function of delay and provided means to quantify the effects of patterns of voice confusability. Signal-detection analysis revealed the similarity of results from diverse experimental paradigms. A "prototype" model is advanced to explain the fact that certain voices are preferentially selected as having been heard previously. The model also unites several previously unconnected findings in the literature on voice recognition and makes testable predictions.