The Interaction of Lexical Semantics and Cohort Competition in Spoken Word Recognition:An fMRI Study

摘要

Spoken word recognition involves the activation of multiplenword candidates on the basis of the initial speech input—then“cohort”—and selection among these competitors. Selectionnmay be driven primarily by bottom–up acoustic–phonetic inputsnor it may be modulated by other aspects of lexical representation,nsuch as a wordʼs meaning [Marslen-Wilson, W. D. Functionalnparallelism in spoken word-recognition. Cognition, 25,n71–102, 1987]. We examined these potential interactions in annfMRI study by presenting participants with words and pseudowordsnfor lexical decision. In a factorial design, we manipulatedn(a) cohort competition (high/low competitive cohorts which varynthe number of competing word candidates) and (b) the wordʼsnsemantic properties (high/low imageability). A previous behavioralnstudy [Tyler, L. K., Voice, J. K., & Moss, H. E. The interactionnof meaning and sound in spoken word recognition. PsychonomicnBulletin & Review, 7, 320–326, 2000] showed that imageabilitynfacilitated word recognition but only for words in highncompetition cohorts. Here we found greater activity in the leftninferior frontal gyrus (BA 45, 47) and the right inferior frontalngyrus (BA 47) with increased cohort competition, an imageabilityneffect in the left posterior middle temporal gyrus/angular gyrusn(BA 39), and a significant interaction between imageability and cohortncompetition in the left posterior superior temporal gyrusmiddle temporal gyrus (BA 21, 22). In words with high competitionncohorts, high imageability words generated stronger activitynthan low imageability words, indicating a facilitatory rolenof imageability in a highly competitive cohort context. For wordsnin low competition cohorts, there was no effect of imageability.nThese results support the behavioral data in showing thatnselection processes do not rely solely on bottom–up acoustic–nphonetic cues but rather that the semantic properties of candidatenwords facilitate discrimination between competitors.