Individual Differences in Language Ability Are Related to Variation in Word Recognition, Not Speech Perception: Evidence From Eye Movements

Abstract

Purpose This study examined speech perception deficits associated with individual differences in language ability contrasting auditory, phonological or lexical accounts by asking if lexical competition is differentially sensitive to fine-grained acoustic variation. Methods 74 adolescents with a range of language abilities (including 35 impaired) participated in an experiment based on McMurray, Tanenhaus and Aslin (2002). Participants heard tokens from six 9-step Voice Onset Time (VOT) continua spanning two words (beach/peach, beak/peak, etc), while viewing a screen containing pictures of those words and two unrelated objects. Participants selected the referent while eye-movements to each picture were monitored as a measure of lexical activation. Fixations were examined as a function of both VOT and language ability. Results Eye-movements were sensitive to within-category VOT differences: as VOT approached the boundary, listeners made more fixations to the competing word. This did not interact with language ability, suggesting that language impairment is not associated with differential auditory sensitivity or phonetic categorization. Listeners with poorer language skills showed heightened competitors fixations overall, suggesting a deficit in lexical processes. Conclusions Language impairment may be better characterized by a deficit in lexical competition (inability to suppress competing words), rather than differences phonological categorization or auditory abilities.

Waiting for lexical access: Cochlear implants or severely degraded input lead listeners to process speech less incrementally

“…Typically developing adolescents (between 9 and 16) show an over abundance of initial competition from cohorts and rhymes, and consequently somewhat slower target activation (Rigler et al, 2015) (see also, Sekerina & Brooks, 2007); however, by the end of processing even 9 year olds fully suppress competitors. In contrast adolescents with poorer language (language impairment) show no early effects on competition but do not fully suppress lexical competitors by the end of processing (McMurray, Munson, & Tomblin, 2014; McMurray et al, 2010) (see also, Dollaghan, 1998), and, as described, post-lingually deaf CI users are somewhat slower to activate target words, and also maintain competitors later.…”

The Downside of Greater Lexical Influences: Selectively Poorer Speech Perception in Noise

“…Children with SLI are less effective in ignoring lexical competitors (McMurray, Munson, & Tomblin, 2014;McMurray, Samelson, Lee, & Tomblin, 2010), and more likely to vacillate on their responses when exposed to word fragments with multiple alternative continuations (Mainela-Arnold, Evans, & Coady, 2008). Children with SLI also display greater lexical influences on speech perception than age-matched controls (Schwartz, Scheffler, & Lopez, 2013).…”

Individual Differences in Subphonemic Sensitivity and Phonological Skills

“…Indeed, studies comparing dichotomous 260 and continuous analytic approaches find better statistical fit when treating language ability as a 261 continuous predictor (e.g., McMurray, Munson, & Tomblin, 2014). Further, there is little 262 evidence of discontinuity between the phonological skills scores of those with and without RD 263 (O'Brien, McCloy, Kubota, & Yeatman, 2018;Ramus et al, 2013;Scarborough, 1989).…”