The case of letter rhyming: An ERP study

Abstract

Previous visual event-related potential (ERP) studies using prime-target pairs of word and pseudoword stimuli have reported a robust rhyming effect such that nonrhyming targets elicit a larger N450 than rhyming targets. However, results of similar studies using simpler linguistic stimuli-single letters-are equivocal. We used lowercase and uppercase letter pairs in a simple ERP prime-target rhyming paradigm to further investigate whether single letters could elicit the typical rhyming effect and, if so, whether the rhyming effect was sensitive to physical orthography (which differed between the case conditions). The typical N450 rhyming effect was observed in both the lowercase and uppercase letter pair conditions, with similar amplitude and latency between conditions. This pattern of results suggests that the N450 rhyming effect is not sensitive to physical (case) orthography and likely primarily indexes phonological processing related to the rhyme task.

The Neurobiology of Rhyme Judgment by Deaf and Hearing Adults: An ERP Study

“…Although this effect is reliably larger at right than left electrodes, Khateb et al (Khateb et al, 2007) report that the actual generators of this modulation may be left temporal and frontal regions during rhyming trials and bilateral temporal regions during non-rhyming trials. Although this component is similar to that found in studies of semantic incongruity (Kutas & Hillyard, 1980b; Kutas & Hillyard, 1980a; Kutas & Hillyard, 1982), it does not appear to be dependent on semantic processing, since the same effect has been found for nonwords (Rugg, 1984a; Coch, Hart, & Mitra, 2008) and single letter stimuli (Coch, George, & Berger, 2008; Coch et al, 2008). Nevertheless, the responses to phonological and semantic incongruity are thought to belong to the same general class of negativities, peaking around 400ms, reflecting a response to a stimulus that does not conform to expectancy (Rugg, 1984a).…”

Letters Rhyme: Electrophysiological Evidence From Children and Adults

“…Replicating previous work showing an uppercase letter rhyming effect in college students (Coch, George, et al, 2008), nonrhyming letter targets elicited more negative waveforms than rhyming letter targets in the 350-550 msec time window in the adult group (condition, F(1, 15) = 49.8, p < .001; see Figure 2A). The typical ERP rhyming effect was widespread across the scalp but largest at right hemisphere, medial, and posterior sites in analyses of non-midline sites (condition × anterior/posterior, F(5, 75) = 4.6, p < .05; condition × hemisphere × anterior/posterior, F(5, 75) = 4.6, p < .05; condition × lateral/medial, F(1, 15) = 47.0, p < .001; condition × anterior/posterior × lateral/medial, F(5, 75) = 10.4, p < .001).…”

“…In previous studies with adults, lowercase and uppercase letters presented in pairs in a typical prime-target ERP rhyming paradigm have been found to elicit the typical ERP N450 rhyming effect (Coch, George, et al, 2008;Coch, Hart, et al, 2008). To our knowledge, single letter stimuli have not been used previously in a prime-target pair ERP rhyming study with children who are beginning readers.…”

“…A handful of ERP studies have used single letter stimuli in rhyming paradigms with children and adults (e.g., Coch, George, & Berger, 2008;Coch, Hart, et al, 2008;Lovrich & Kazmerski, 1993;Lovrich, Kazmerski, Cheng, & Geisler, 1994;Taylor, 1993). However, in previous studies with children, letter stimuli were presented singly, in list form, and children were asked to respond to any letters that rhymed with a given letter (Lovrich & Kazmerski, 1993;Lovrich et al, 1994;Taylor, 1993).…”

“…This time window was determined based on visual analysis of individual participant waveforms and grand averages across participants; this window has also been used in a previous study of letter rhyming in adults (Coch, George, et al, 2008). Peak latency was measured as the most negative data point within the time window such that the preceding and following three data points were less negative in order to avoid local minima.…”