Poster Session C, Sunday, March 24, 5:00 – 7:00 pm, Pacific Concourse
Tracking the time-course of visual word recognition using different types of word-like stimuli
Natasja Massa1, Karen Emmorey1, Katherine J. Midgley1, Phillip J. Holcomb1; 1San Diego State University
The ability to rapidly recognize visually perceived words is fundamental to skilled reading. The present study used ERPs to track the time-course of the neuro-cognitive processes involved in visual word recognition. Prior work has shown that the lateral distribution of the N170 is sensitive to early processing differences between linguistic (words) and nonlinguistic (symbol strings) stimuli, while later ERP components such as the N250 and N400 are sensitive to sub-lexical and lexico-semantic processes, respectively. We contrasted ERPs to minimally different categories of word-like visual stimuli in a group of monolingual English speakers engaged in a go/no-go repetition detection task. ERPs were time-locked to five types of visual stimuli including words (e.g., “table”), pseudohomophones (e.g., “brane”), pseudowords (e.g., “wruck”), random consonant strings (e.g., tblnr), and strings of symbols (e.g., $%&*^). The early N170 was larger over the left hemisphere compared to the right hemisphere for all stimuli composed of letters, while symbol strings generated a more bilateral response. There was no difference in the laterality of the early N170 among any of the letter-based categories and it was only slightly later (after 200 ms) that these stimulus categories started to differ. Between 200 and 300 ms there were differences between consonant strings and the three orthotactically legal stimuli (which did not differ from one another). All three orthotactically legal categories produced greater negativities than either consonant strings or symbol strings. These results will be discussed in the context of recent models of word recognition and orthographic tuning.
Topic Area: LANGUAGE: Lexicon