Author: Ted A. Meyer, David B. Pisoni, Paul A. Luce, and Robert C. Bilger
Abstract:
Luce and Pisoni (in press) developed a model of spoken word recognition based on
neighborhood probability characteristics of monosyllabic words. This model, known
as the Neighborhood Activation Model (NAM), assumes that words are recognized in
the context of other similar sounding patterns in the lexicon. NAM predicts that
word recognition is dependent on how easy or difficult it is to confuse the
stimulus word with phonetically similar words in a lexical neighborhood. Cluff and
Luce (1990) demonstrated that spondaic word recognition is also dependent on the
confusability of the individual syllables. Spondaic words with two easy to
recognize syllables are identified more accurately than spondaic words with two
hard to recognize syllables. Recently, Bilger et al. (submitted) analyzed the 36
spondaic words [Tillman et al. (1963) recording of the Hirsh et al. (1952)
spondaic words] currently used to determine the speech reception threshold (SRT)
(American Speech-Language-Hearing Association, 1988). They found that the
thresholds and slopes of psychometric functions for the spondaic words were not
equivalent, and that the spondees were not equally intelligible. In this study, we
computed the lexical neighborhood characteristics (Pisoni et al., 1985) of the
individual syllables in these spondaic words and compared these values to
psychophysical and acoustic measures obtained from Bilger et al. Although spondaic
word thresholds were not related to any of the lexical neighborhood measures of
the words, the slopes of the psychometric functions were negatively correlated
with the neighborhood densities of the spondaic words. This finding demonstrates
that the rate at which a word becomes intelligible is inversely related to the
confusability of the word with its lexical neighbors in memory. Implications for
the development of new tests for speech discrimination are discussed.