Visual word recognition is commonly rapid and efficient, incorporating top–down predictive processing mechanisms. Neuroimaging studies with face stimuli suggest that repetition suppression (RS) reflects predictive processing at the neural level, as this effect is larger when repetitions are more frequent, that is, more expected. It remains unclear, however, at the temporal level whether and how RS and its modulation by expectation occur in visual word recognition. To address this gap, the present study aimed to investigate the presence and time course of these effects during visual word recognition using EEG. Thirty-six native Cantonese speakers were presented with pairs of Chinese written words and performed a nonlinguistic oddball task. The second word of a pair was either a repetition of the first or a different word (alternation). In repetition blocks, 75% of trials were repetitions and 25% were alternations, whereas the reverse was true in alternation blocks. Topographic analysis of variance of EEG at each time point showed robust RS effects in three time windows (141–227 msec, 242–445 msec, and 467–513 msec) reflecting facilitation of visual word recognition. Importantly, the modulation of RS by expectation was observed at the late rather than early intervals (334–387 msec, 465–550 msec, and 559–632 msec) and more than 100 msec after the first RS effects. In the predictive coding view of RS, only late repetition effects are modulated by expectation, whereas early RS effects may be mediated by lower-level predictions. Taken together, our findings provide the first EEG evidence revealing distinct temporal dynamics of RS effects and repetition probability on RS effects in visual processing of Chinese words.

Neural correlates of word recognition are commonly studied with (rapid) serial visual presentation (RSVP), a condition that eliminates three fundamental properties of natural reading: parafoveal preprocessing, saccade execution, and the fast changes in attentional processing load occurring from fixation to fixation. We combined eye-tracking and EEG to systematically investigate the impact of all three factors on brain-electric activity during reading. Participants read lists of words either actively with eye movements (eliciting fixation-related potentials) or maintained fixation while the text moved passively through foveal vision at a matched pace (RSVP-with-flankers paradigm, eliciting ERPs). The preview of the upcoming word was manipulated by changing the number of parafoveally visible letters. Processing load was varied by presenting words of varying lexical frequency. We found that all three factors have strong interactive effects on the brain's responses to words: Once a word was fixated, occipitotemporal N1 amplitude decreased monotonically with the amount of parafoveal information available during the preceding fixation; hence, the N1 component was markedly attenuated under reading conditions with preview. Importantly, this preview effect was substantially larger during active reading (with saccades) than during passive RSVP with flankers, suggesting that the execution of eye movements facilitates word recognition by increasing parafoveal preprocessing. Lastly, we found that the N1 component elicited by a word also reflects the lexical processing load imposed by the previously inspected word. Together, these results demonstrate that, under more natural conditions, words are recognized in a spatiotemporally distributed and interdependent manner across multiple eye fixations, a process that is mediated by active motor behavior.

Recent evidence suggests that conceptual knowledge modulates early visual stages of object recognition. The present study investigated whether similar modulations can be observed also for the recognition of object names, that is, for symbolic representations with only arbitrary relationships between their visual features and the corresponding conceptual knowledge. In a learning paradigm, we manipulated the amount of information provided about initially unfamiliar visual objects while controlling for perceptual stimulus properties and exposure. In a subsequent test session with electroencephalographic recordings, participants performed several tasks on either the objects or their written names. For objects as well as names, knowledge effects were observed as early as about 120 msec in the P1 component of the ERP, reflecting perceptual processing in extrastriate visual cortex. These knowledge-dependent modulations of early stages of visual word recognition suggest that information about word meanings may modulate the perception of arbitrarily related visual features surprisingly early.

Individual differences in perceiving, learning, and recognizing faces, summarized under the term face cognition, have been shown on the behavioral and brain level, but connections between these levels have rarely been made. We used ERPs in structural equation models to determine the contributions of neurocognitive processes to individual differences in the accuracy and speed of face cognition as established by Wilhelm, Herzmann, Kunina, Danthiir, Schacht, and Sommer [Individual differences in face cognition, in press]. For 85 participants, we measured several ERP components and, in independent tasks and sessions, assessed face cognition abilities and other cognitive abilities, including immediate and delayed memory, mental speed, general cognitive ability, and object cognition. Individual differences in face cognition were unrelated to domain-general visual processes (P100) and to processes involved with memory encoding (Dm component). The ability of face cognition accuracy was moderately related to neurocognitive indicators of structural face encoding (latency of the N170) and of activating representations of both faces and person-related knowledge (latencies and amplitudes of the early and late repetition effects, ERE/N250 and LRE/N400, respectively). The ability of face cognition speed was moderately related to the amplitudes of the ERE and LRE. Thus, a substantial part of individual differences in face cognition is explained by the speed and efficiency of activating memory representations of faces and person-related knowledge. These relationships are not moderated by individual differences in established cognitive abilities.

Whether syntactic and semantic processes during sentence comprehension follow strict sets of rules or succumb to context-dependent heuristics was studied by recording event-related potentials in a dual-task design. In one condition, sentence-extraneous acoustic material was either semantically congruent or incongruent relative to an adjective in the visually presented sentence, the latter being either semantically correct or incorrect within the sentence context. Homologous syntactic (gender) manipulations were performed in another condition. Syntactic processing within the sentence appeared to be blind to the syntactic content of the second task. In contrast, semantically incongruous material of the second task induced fluctuations typically associated with the detection of within-sentence semantic anomalies (N400) even in semantically correct sentences. Subtle but extant differences in topography between this N400 and that obtained with within-sentence semantic violations add to recent proposals of separate semantic subsystems differing in their specificity for sentence structure and computational procedures. Semantically incongruous material of the second task also influenced later stages of the processing of semantically incorrect adjectives (P600 component), which are traditionally assumed to pertain to the syntactic domain. This result is discussed in the light of current proposals of a third combinatorial stream in sentence comprehension.