Poster E32, Saturday, August 18, 3:00 – 4:45 pm, Room 2000AB
Frequency, orthographic neighborhood, and concreteness effects in deaf readers of English: An ERP study
Stephanie Osmond1, Kurt Winsler2, Gabriela Meade1,3, Phillip J Holcomb1, Katherine J Midgley1, Karen Emmorey1;1San Diego State University, 2University of California, Davis, 3University of California, San Diego
Early event-related potential (ERP) components differ between skilled deaf and hearing readers. For example, a recent ERP study found differences in the N170 to words compared to symbols when comparing deaf and hearing readers (Emmorey et al., 2017). Hearing readers showed a larger difference in N170 amplitude between words and symbol strings, especially over left temporal-parietal sites, while skilled deaf readers showed smaller and less asymmetrical differences. These patterns suggest that during the early stages of processing, hearing and deaf readers differ in the underlying mechanisms involved in visual word recognition. Very little research has compared deaf and hearing readers on language-sensitive ERP components later than the N170. Extending the focus to these later downstream components is important because collectively they reflect important aspects of language comprehension that might also distinguish hearing and deaf readers. Previous ERP studies in hearing English speakers have shown that several word-level variables have a robust effect on ERP components starting around 200 ms after word onset: lexical frequency, or how often a word is encountered in English, neighborhood size, or how many other words the word looks like, and concreteness, or the degree to which the concept that the word refers to is concrete or abstract in nature. These three characteristics have been shown to produce systematic differences in the timing, amplitude, and scalp patterns of various post-N170 ERP components. The current study extended observations of the effects of these variables on ERPs from hearing participants to deaf readers of English. We hypothesized that if the differing pattern of early N170 effects reported by Emmorey et al. (2017) is indicative of a completely different set of reading mechanisms in deaf readers, then later downstream processes involved in reading might also differ between these two groups. Deaf participants who report American Sign Language as their primary and preferred language, but are also proficient readers of English, were asked to decide if written words presented one by one were real English words [e.g., table] or nonwords [e.g., flark]. Participants pressed only to nonwords [12% of items]. Words varied in lexical frequency, orthographic neighborhood density, and conceptual concreteness. Deaf readers produced a very similar pattern of ERP effects to those seen in hearing readers across the three variables that we manipulated, suggesting that the post N170 mechanisms involved in recognizing visual words are similar for hearing and deaf readers.
Topic Area: Meaning: Lexical Semantics