Processing Metrical Information in Silent Reading: An ERP Study

Abstract

Listeners are sensitive to the metric structure of words, i.e., an alternating pattern of stressed and unstressed syllables, in auditory speech processing: Event-related potentials recorded as participants listen to a sequence of words with a consistent metrical pattern, e.g., a series of trochaic words, suggest that participants register words metrically incongruent with the preceding sequence. Here we examine whether the processing of individual words in silent reading is similarly impacted by rhythmic properties of the surrounding context. We recorded participants’ EEG as they read lists of either three trochaic or iambic disyllabic words followed by a target word that was either congruent or incongruent with the preceding metric pattern. Event-Related Potentials (ERPs) to targets were modulated by an interaction between metrical structure (iambic vs. trochaic) and congruence: for iambs, more positive ERPs were observed in the incongruent than congruent condition 250–400 ms and 400–600 ms post-stimulus, whereas no reliable impact of congruence was found for trochees. We suggest that when iambs are in an incongruent context, i.e., preceded by trochees, the context contains the metrical structure that is more typical in participants’ native language which facilitates processing relative to when they are presented in a congruent context, containing the less typical, i.e., iambic, metrical structure. The results provide evidence that comprehenders are sensitive to the prosodic properties of the context even in silent reading, such that this sensitivity impacts lexico-semantic processing of individual words.

Event-Related Potential Evidence of Implicit Metric Structure during Silent Reading

“…In general, these studies demonstrate that, similar to explicit metric violations, implicit metric violations often evoke an early negativity that is more reliably observed for SW than WS violations. Moreover, two of these studies are consistent with results from explicit meter studies in that when the task does not require an explicit metric judgment (and none of these did; rather, participants’ task was to make an old/new judgment of the target [53], a lexical decision judgment [55], or answer a semantic question about the word strings [54]), there is no late positivity.…”

“…Cluster magnitudes were then calculated as the sum of all t -scores for electrodes contained within a cluster. Lower-tailed t -tests were used for the SW comparisons based on prior findings that SW violations consistently elicit relative negativities [36,41,44,45,49,53,55], whereas two-tailed t -tests were used for the WS comparisons based on prior findings that WS violations elicit both relative negativities and positivities [40,41,42,54]. This process was replicated over 5000 shuffled iterations, and a cluster magnitude threshold was defined as the magnitude that clusters met or exceeded on only 5% of the shuffled (i.e., chance) iterations.…”

“…In another study exploring silent metric processing in word lists, readers were presented with strings of three two-syllable German prime words followed by a SW or WS target. In this case, there were no observable ERP differences for SW violations, but WS violations were more positive than correct WS targets in three time windows: between 250–400, 400–600, and 600–800 ms after target onset [54]. A final study presented participants with an auditory tone sequence with a SW or WS pattern followed by a visually presented two-syllable English word which was consistent or inconsistent with the tone sequence stress pattern [55].…”

Sentence-Level Effects of Literary Genre: Behavioral and Electrophysiological Evidence

“…For instance, Rothermich and colleagues reported modulations of N400 amplitudes depending on prosodic context, which they interpreted as evidence that the predictability of stress locations facilitates lexico-semantic processing. Importantly, N400-like prosodic negativities have been reported for silent reading as well (e.g., Luo and Zhou, 2010 ; Magne et al, 2010 ), in line with mounting evidence that implicit prosody ( Fodor, 1998 ) co-determines the comprehension of written text (e.g., Bader, 1998 ; Steinhauer and Friederici, 2001 ; Stolterfoht et al, 2007 ; Breen and Clifton, 2011 ; Kentner, 2012 ; Kentner and Vasishth, 2016 ; Kriukova and Mani, 2016 ; see Breen, 2014 for a recent review).…”

Early markers of lexical stress in visual word recognition

“…To our knowledge, this is also the earliest marker of stress assignment ever reported during the time-course of stress assignment in visual word recognition of isolated words. Indeed, other EEG-based studies on stress assignment of isolated words show rather late effects (Kriukova & Mani, 2016). Moreover, non-dominant stress consistent and nondominant stress inconsistent words still did not differ, suggesting that consistency effects were not present.…”