Effects of lexical ambiguity, frequency, and acoustic details in auditory perception.

This paper presents a set of auditory perception experiments testing the effects of lexical ambiguity, lemma frequency, and acoustic details. In an AX discrimination task with stimuli produced in isolation, lexically ambiguous phonologically matching forms (e.g., sun-sun, sun-son) were evaluated more slowly and identified as 'different' more often than lexically unambiguous forms (e.g., cat-cat). For stimuli extracted from meaningful sentences, pairs of homophone mates (sun-son) were evaluated more slowly than same pairs of such words (sun-sun), following from the greater acoustic distance between homophone mates in several measures. The individual lexical frequency of homophone mates was a significant factor in both identification tasks, though frequency effects in the AX tasks were weaker and driven by the lexically unambiguous items. In both studies, greater acoustic distance between items was a predictor of longer response times, though the significance of particular acoustic measures varied. Identification of homophone mates also depended on context of production; listeners were above chance accuracy for choosing between homophone mates extracted from sentences, but not for homophone mates produced in isolation. While results for stimuli produced in sentential contexts indicate that listeners are sensitive to acoustic details and can weakly associate production patterns with lexical items, the absence of such differences for homophone mates produced in isolation suggests that these details are not an inherent part of the representation.