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Different Needs, Different Speeds: Automatic Spreading Activation Timing Varies with Language Ability in School-Age Children
Poster Session E, Friday, October 2, 11:00 am - 1:00 pm, Wangari Maathai
Ashlie Pankonin1,2, Jacqueline Zhang1,2, Alyson Abel1; 1San Diego State University, 2University of California, San Diego
Language ability relies on numerous unconscious processes, including semantic processing. Subtle differences in this semantic processing may, thus, contribute to variability in language ability. One proposed mechanism underlying semantic processing is automatic spreading activation, in which activation propagates through the lexical-semantic system. Although atypical spreading activation timing has been implicated in language disorders (e.g., aphasia, developmental language disorder), less is known about how variability in the temporal dynamics of automatic spreading activation relates to language ability across the broader continuum of language functioning. The current study examined whether differences in the timing of automatic spreading activation are associated with global language ability in school-age children of varying language skills. Forty-one children aged 7;11 to 14;3 whose language skills ranged from impaired to above average completed a standardized assessment of global language ability, the Clinical Evaluation of Language Fundamentals–Fourth Edition (CELF-4), and an EEG masked priming task. The CELF-4 scores quantified participants’ skills in morphology, semantics, and syntax, and the priming task was designed to probe the temporal dynamics of automatic spreading activation. During the priming task, participants completed a go/no-go semantic categorization task for animal words while viewing sequentially presented masked primes and visible targets. Critical trials consisted of repeated (primed) or unrelated (unprimed) non-animal words. Prime-target interval length (short vs. long interstimulus interval [ISI]) was manipulated to assess how semantic activation unfolded over time. Neural priming effects were indexed by modulation of the N400 component, which reflects automatic semantic processing and is sensitive to facilitation of that processing by priming. To examine whether neural priming predicted language ability, we evaluated the interaction among priming, ISI, and CELF-4 scores. Results revealed a significant three-way interaction, indicating that patterns of N400 priming differed across language ability levels and ISIs. At the short ISI, priming effects strengthened as language ability increased. Children with weaker language ability showed little to no N400 priming effect at the short ISI, whereas children with stronger language ability demonstrated clear facilitated neural processing of primed targets. At the long ISI, priming effects followed a different pattern, strengthening with increasing language ability up through average levels, where priming was strongest, before decreasing again at higher levels of language ability. Together, these findings suggest that the ISI that maximally facilitated semantic processing varied as a function of language ability, potentially reflecting differences in the spreading activation timing based on language skill. The results provide evidence that differences in the temporal dynamics of automatic spreading activation are associated with broad language ability in school-age children and raise the possibility that spreading activation timing varies systematically with language ability, even among children without clinically significant impairment. Thus, variability in the neural mechanisms of semantic processing may underlie observable differences in language ability across the spectrum of language functioning.
Topic Areas: Meaning: Lexical Semantics, Disorders: Developmental