Individual differences in cocktail party listening: The relative role of decision weights and internal noise

Abstract

A simulated 'cocktail-party' listening experiment was conducted to determine the relative role of decision weights and internal noise in accounting for the large individual differences in performance typically observed in these experiments. The listener heard over headphones interleaved sequences of random vowels and were asked to judge on each trial whether the vowels were spoken by the same AAA or different ABA talkers. The A and B vowels had nominally different Fo and spatial position (simulated using Kemar HRTFs), but were randomly perturbed around these values on each presentation. Decision weights for each dimension, internal noise, and efficiency measures were estimated using COSS analysis [Berg (1990). J. Acoust. Soc. Am. 88:149-158]. Decision weights differed across listeners, but weighting efficiency was quite similar. Individual differences in performance accuracy ranging over 40 percentage points were largely related to differences in internal noise. The results are discussed in terms of their implications for the relative role of sensory and attentional factors affecting individual performance differences in simulated cocktail party listening.