ERP Evidence for Ultra-Fast Semantic Processing in the Picture–Word Interference Paradigm (original) (raw)
Related papers
Brain and language, 2013
In this study, we investigated how people deal with irrelevant contextual information during speech production. Two main models have been proposed. WEAVER++ assumes that irrelevant information is removed from the production system by an early blocking mechanism. On the other hand, the response exclusion hypothesis assumes a blocking mechanism that operates late, after lexical selection has finished. To delineate between these models, we focused on the distractor frequency effect (i.e., longer picture naming latencies in the context of low-frequency compared to high-frequency words) and measured ERPs concurrently. Behaviorally, the distractor frequency effect was replicated. In the ERPs, three effects were found. One effect occurred very early and is interpreted as an effect of low-level visual feature processing. The two other effects occurred after lexical access and are thus in line with the response exclusion hypothesis.
Picture–word interference is a widely employed paradigm to investigate lexical access in word production: Speakers name pictures while trying to ignore superimposed distractor words. The distractor can be congruent to the picture (pictured cat, word cat), categorically related (pictured cat, word dog), or unrelated (pictured cat, word pen). Categorically related distractors slow down picture naming relative to unrelated distractors, the so-called semantic interference. Categorically related distractors slow down picture naming relative to congruent distractors, analogous to findings in the colour–word Stroop task. The locus of semantic interference and Stroop-like effects in naming performance has recently become a topic of debate. Whereas some researchers argue for a pre-lexical locus of semantic interference and a lexical locus of Stroop-like effects, others localise both effects at the lexical selection stage. We investigated the time course of semantic and Stroop-like interference effects in overt picture naming by means of event-related potentials (ERP) and time–frequency analyses. Moreover, we employed cluster-based permutation for statistical analyses. Naming latencies showed semantic and Stroop-like interference effects. The ERP waveforms for congruent stimuli started diverging statistically from categorically related stimuli around 250 ms. Deflections for the categorically related condition were more negative-going than for the congruent condition (the Stroop-like effect). The time–frequency analysis revealed a power increase in the beta band (12–30 Hz) for categorically related relative to unrelated stimuli roughly between 250 and 370 ms (the semantic effect). The common time window of these effects suggests that both semantic interference and Stroop-like effects emerged during lexical selection.► We examined the locus of semantic and Stroop-like effects in naming performance. ► We employed event-related potentials (ERP) and time–frequency (TF) analyses. ► ERP waveforms showed a Stroop-like effect starting around 250 ms. ► TF analyses revealed beta power increase between 250 and 370 ms for the semantic effect. ► The common time window of the effects suggests they emerged during lexical selection.
A major effort in cognitive neuroscience of language is to define the temporal and spatial characteristics of the core cognitive processes involved in word production. One approach consists in studying the effects of linguistic and pre-linguistic variables in picture naming tasks. So far, studies have analyzed event-related potentials (ERPs) during word production by examining one or two variables with factorial designs. Here we extended this approach by investigating simultaneously the effects of multiple theoretical relevant predictors in a picture naming task. High density EEG was recorded on 31 participants during overt naming of 100 pictures. ERPs were extracted on a trial by trial basis from picture onset to 100 ms before the onset of articulation. Mixed-effects regression models were conducted to examine which variables affected production latencies and the duration of periods of stable electrophysiological patterns (topographic maps). Results revealed an effect of a pre-linguistic variable, visual complexity, on an early period of stable electric field at scalp, from 140 to 180 ms after picture presentation, a result consistent with the proposal that this time period is associated with visual object recognition processes. Three other variables, word Age of Acquisition, Name Agreement, and Image Agreement influenced response latencies and modulated ERPs from ∼380 ms to the end of the analyzed period. These results demonstrate that a topographic analysis fitted into the single trial ERPs and covering the entire processing period allows one to associate the cost generated by psycholinguistic variables to the duration of specific stable electrophysiological processes and to pinpoint the precise time-course of multiple word production predictors at once.
ERP correlates of unexpected word forms in a picture–word study of infants and adults
Developmental Cognitive Neuroscience, 2012
"We tested 14-month-olds and adults in an event-related potentials (ERPs) study in which pictures of familiar objects generated expectations about upcoming word forms. Expected word forms labelled the picture (word condition), while unexpected word forms mismatched by either a small deviation in word medial vowel height (mispronunciation condition) or a large deviation from the onset of the first speech segment (pseudoword condition). Both infants and adults showed sensitivity to both types of unexpected word form. Adults showed a chain of discrete effects: positivity over the N(1) wave, negativity over the P(2) wave (PMN effect) and negativity over the N(2) wave (N400 effect). Infants showed a similar pattern, including a robust effect similar to the adult P(2) effect. These observations were underpinned by a novel visualisation method which shows the dynamics of the ERP within bands of the scalp over time. The results demonstrate shared processing mechanisms across development, as even subtle deviations from expected word forms were indexed in both age groups by a reduction in the amplitude of characteristic waves in the early auditory evoked potential. Citation: Duta, M. D., S. J. Styles, et al. (2012). "ERP correlates of unexpected word forms in a picture-word study of infants and adults." Developmental Cognitive Neuroscience 2: 223-234."