The FN400 is functionally distinct from the N400

Separating the role of perceptual and conceptual fluency on masked word priming using event-related potentials

Masked word repetition increases "old" responses on an episodic recognition test (Jacoby & Whitehouse, 1989). This effect is commonly attributed to perceptual fluency; that is, unconscious perception of the prime speeds reading of the target and this fluency leads to elevated familiarity. Two experiments directly tested the claim that perceptual fluency is responsible for word priming effects. Experiment 1 held prime-target meaning constant and altered the physical characteristics of match primes (e.g., "RIGHT" primes "RIGHT") by including both lowercase (e.g, "right") and mixed case primes (e.g., "rIgHt"). If word priming effects are due to perceptual fluency, then lowering the perceptual overlap between the prime and target should decrease or eliminate word priming effects. Instead, all three conditions showed robust priming effects in the behavioral and ERP (i.e., N400) measures. Experiment 2 equated the prime-target perceptual features and lowered the conceptual overlap by using orthographically similar nonwords as primes (e.g., "JIGHT" primes "RIGHT"). Removing prime-target conceptual overlap eliminated behavioral evidence of priming and N400 ERP differences correlated with priming. The evidence suggests that word priming effects on episodic recognition memory are more likely a product of conceptual fluency than perceptual fluency.

An ERP measure of non-conscious memory reveals dissociable implicit processes in human recognition using an open-source automated analytic pipeline

Non-conscious processing of human memory has traditionally been difficult to objectively measure and thus understand. A prior study on a group of hippocampal amnesia (N = 3) patients and healthy controls (N = 6) used a novel procedure for capturing neural correlates of implicit memory using event-related potentials (ERPs): old and new items were equated for varying levels of memory awareness, with ERP differences observed from 400 to 800 ms in bilateral parietal regions that were hippocampal-dependent. The current investigation sought to address the limitations of that study by increasing the sample of healthy subjects (N = 54), applying new controls for construct validity, and developing an improved, open-source tool for automated analysis of the procedure used for equating levels of memory awareness. Results faithfully reproduced prior ERP findings of parietal effects that a series of systematic control analyses validated were not contributed to nor contaminated by explicit memory. Implicit memory effects extended from 600 to 1000 ms, localized to right parietal sites. These ERP effects were found to be behaviorally relevant and specific in predicting implicit memory response times, and were topographically dissociable from other traditional ERP measures of implicit memory (miss vs. correct rejections) that instead occurred in left parietal regions. Results suggest first that equating for reported awareness of memory strength is a valid, powerful new method for revealing neural correlates of non-conscious human memory, and second, behavioral correlations suggest that these implicit effects reflect a pure form of priming, whereas misses represent fluency leading to the subjective experience of familiarity.

EEG-based univariate and multivariate analyses reveal that multiple processes contribute to the production effect in recognition

The production effect (PE) is the finding that reading words aloud rather than silently during study leads to improved memory. We used electroencephalography (EEG) techniques to detect the contributions of recollection, familiarity, and attentional processes to the PE in recognition memory, using Chinese stimuli. During the study phase, participants encoded each list item aloud, silently, or by performing a non-unique aloud (control) task. During the test phase, they made remember/know/new recognition judgments. We recorded EEG data in both phases. The behavioral results replicated the typical pattern with English stimuli: Recognition was better in the aloud condition than in the silent (and control) condition, and this PE was due to enhanced recollection and familiarity. At study, the amplitude of the P3b ERP component was greater in the aloud than in the silent/control conditions, suggesting that reading aloud increases attention or preparatory processing during the intention phase. At test, the recollection-based LPC old/new effect was largest in the aloud condition; however, the familiarity-based FN400 old/new effect was equivalent between the aloud condition and the silent/control conditions. Only the LPC effect correlated with the behavioral effect. Moreover, multivariate pattern analysis (MVPA) showed that accurate classification of items as 'aloud' versus 'new' mainly occurred in the later period of the recognition response, consistent with the LPC old/new effect. Our findings suggest that the within-subject PE in recognition memory reflects enhanced attention and distinctiveness, rather than increased memory strength. More broadly, our findings suggest that encoding strategies such as production enhance recollection more than familiarity.

Effects of emotion words activation and satiation on facial expression perception: evidence from behavioral and ERP investigations

Objective

The present study investigated the impact of emotion concepts obtained from external environmental experiences on the perception of facial expressions by manipulating the activation and satiation of emotion words, which was based on the argument between basic emotion theory and constructed emotion theory.

Methods

Experiment 1 explored the effects of emotion activation on happy, disgusted, emotion-label words and emotion-laden words in a facial expression judgment task through behavioral experimentation. Experiment 2 explored the effect of semantic satiation on emotion-label words and emotion-laden words using the event-related potential technique.

Results

Experiment 1 found that facial expression perception was influenced by both types of emotion words and showed a significant emotional consistency effect. Experiment 2 found that N170 exhibited a more negative amplitude in the consistent condition compared to the inconsistent condition in the right hemisphere. More importantly, in the later stage of facial expression processing, emotion-label words and emotion-laden words both obstructed the perception of disgusted facial expressions and elicited more negative N400 amplitude in the emotion consistency condition, showing a reversed N400 effect.

Conclusion

These results suggested that emotion concepts in the form of language influenced the perception of facial expressions, but there were differences between happy and disgusted faces. Disgusted faces were more dependent on emotion concept information and showed different performances in semantic activation and satiation conditions.

Event-Related Potential (ERP) evidence for fluency and disfluency effects on recognition memory

Masked priming is used in recognition memory studies to alter fluency and create familiarity. Primes are flashed briefly before target words that are considered for a recognition judgment. Matching primes are hypothesized to produce greater familiarity by increasing the perceptual fluency of the target word. Experiment 1 tested this claim by contrasting match primes (i.e., "RIGHT" primes "RIGHT"), semantic primes (e.g., "LEFT" primes "RIGHT"), and orthographically similar (OS) primes (e.g., "SIGHT" primes "RIGHT") while recording event-related potentials (ERPs). Relative to match primes, OS primes elicited fewer "old" responses and more negative ERPs during the interval associated with familiarity (300-500 ms). This result was replicated when control primes consisting of unrelated words (Experiment 2) or symbols (Experiment 3) were inserted into the sequence. The behavioral and ERP evidence suggest that word primes are perceived as a unit and the prime word activation will affect target fluency and recognition judgments. When the prime matches the target, fluency is increased and more familiarity experiences are created. When the primes are words that do not match the target, fluency is decreased (disfluency) and fewer familiarity experiences result. This evidence suggests that the effects of disfluency on recognition should be carefully considered.

The role of subjective significance, valence and arousal in the explicit processing of emotion-laden words

Emotional categorisation (deciding whether a word is emotional or not) is a task that employs the explicit analysis of the emotional meaning of words. Therefore, it allows for assessing the role of emotional factors, i.e., valence, arousal, and subjective significance, in emotional word processing. The aim of the current experiment was to investigate the role of subjective significance, a reflective form of activation that is similar to arousal (the automatic form), in the processing of emotional meaning. We applied the orthogonal manipulation of three emotional factors. Thus, we were able to precisely differentiate the effects of each factor and search for interactions between them. We expected valence to shape the late positive complex LPC component, while subjective significance and arousal were expected to shape the P300 and N400 components. We observed the effects of subjective significance throughout the whole span of processing, while the arousal effect was present only in the LPC component. We also observed that amplitudes for N400 and LPC discriminated negative from positive valence. The results showed that all factors included in the analysis should be taken into account while explaining the processing of emotion-laden words; especially interesting is the subjective significance, which was shown to shape processing individually, as well as to come into interaction with valence and arousal.

Context dissociations of the FN400 and N400 are evidence for recognition based on relative or absolute familiarity

Fluency, the ease of processing, can increase familiarity and the ability to recognize previously encountered information. Mixing or blocking the pre-experimental familiarity of test probes alters the pattern of recognition Event-Related Potentials (ERPs) for picture stimuli (Bruett & Leynes, 2015). The present study tested this idea further by mixing or blocking pre-experimental familiarity of word stimuli. A test with only pre-experimentally familiar words (Experiment 1) elicited the prototypical mid-frontal FN400 old/new ERP difference, which is a correlate of familiarity. However, tests with a mix of pre-experimentally familiar and unfamiliar words (Experiment 2) elicited posterior N400 old/new differences. Based on the Unexpected Fluency Attribution model (Mecklinger & Bader, 2020), this pattern of results suggests that pre-experimental fluency can influence the use of relative (changes from recent exposure) or absolute (baseline levels accrued from experience) familiarity to make a recognition judgment.

Individual differences in behavioral and electrophysiological signatures of familiarity- and recollection-based recognition memory

Our everyday memories can vary in terms of accuracy and phenomenology. According to one theoretical account, these differences hinge on whether the memories contain information about both an item itself as well as associated details (remember) versus those that are devoid of these associated contextual details (familiar). This distinction has been supported by computational modeling of behavior, studies in patients, and neuroimaging work including differences both in electrophysiological and functional magnetic resonance imaging. At present, however, little evidence has emerged to suggest that neurophysiological measures track individual differences in estimates of recollection and familiarity. Here, we conducted electrophysiological recordings of brain activity during a recognition memory task designed to differentiate between behavioral indices of recollection and familiarity. Non-parametric cluster-based permutation analyses revealed associations between electrophysiological signatures of familiarity and recollection with their respective behavioral estimates. These results support the idea that recollection and familiarity are distinct phenomena and is the first, to our knowledge, to identify distinct electrophysiological signatures that track individual differences in these processes.

The more you know: Schema-congruency supports associative encoding of novel compound words. Evidence from event-related potentials

We aimed to investigate the neurocognitive mechanisms of event congruency with prior (schema) knowledge for the learning of novel compound words. Event-related potentials (ERPs) were recorded during an incidental learning task, in which novel noun-noun compounds were presented in a semantically congruent context, enabling schema-supported processing, or in a neutral context. As expected, associative memory performance was better for compounds preceded by a congruent context. Although the N400 was attenuated in the congruent condition, subsequent memory effects (SMEs) in the N400 time interval did not differ across conditions, suggesting that the processes reflected in the N400 cannot account for the memory advantage in the congruent condition. However, a parietal SME was obtained for compounds preceded by a congruent context, only, which we interpret as reflecting the schema-supported formation of a conceptual compound representation. A late frontal SME was obtained in both conditions, presumably reflecting the more general inter-item associative encoding of compound constituents.

The effect of test query on recognition event-related potentials (ERPs)

The influence of question framing (i.e., [was the item] "old?" or "new?") on recognition memory and event-related potentials (ERPs) was investigated. Words were encoded using a shallow task to create a weak memory trace that was more susceptible to test question framing effects. Participants made yes/no judgments on two, counterbalanced tests. One test focused on old items ("old?"), whereas the other test focused on new items ("new?"). The behavioral evidence suggested that the weak memory traces led to more familiarity-based recognition judgments with a concentrated effect on decision criterion. There were some small ERP changes on the FN400 or LPC consistent with the criterion changes, but the test query did not directly alter these ERP components. Instead, the test query altered a late old/new ERP difference similar to the "right frontal old/new effect" reported in source monitoring ERP studies. When the query was "new?", old items elicited more positive ERPs, whereas there was no old/new difference when the query was "old?". The results suggest that the query framing induces memory biases that occur late in the stream of processing. More generally, the results indicate that decision criterion must be accounted for when interpreting physiological correlates of recognition memory.

Semantic Congruence Drives Long-Term Memory and Similarly Affects Neural Retrieval Dynamics in Young and Older Adults

Learning novel information can be promoted if it is congruent with already stored knowledge. This so-called semantic congruence effect has been broadly studied in healthy young adults with a focus on neural encoding mechanisms. However, the impacts on retrieval, and possible impairments during healthy aging, which is typically associated with changes in declarative long-term memory, remain unclear. To investigate these issues, we used a previously established paradigm in healthy young and older humans with a focus on the neural activity at a final retrieval stage as measured with electroencephalography (EEG). In both age groups, semantic congruence at encoding enhanced subsequent long-term recognition memory of words. Compatible with this observation, semantic congruence led to differences in event-related potentials (ERPs) at retrieval, and this effect was not modulated by age. Specifically, congruence modulated old/new ERPs at a fronto-central (Fz) and left parietal (P3) electrode in a late (400–600 ms) time window, which has previously been associated with recognition memory processes. Importantly, ERPs to old items also correlated with the positive effect of semantic congruence on long-term memory independent of age. Together, our findings suggest that semantic congruence drives subsequent recognition memory across the lifespan through changes in neural retrieval processes.

Consistency and regularity effects in character identification: A greater role for global than local mapping congruence

Consistency and regularity, concepts that arise, respectively, from the connectionist and classical cognitive modeling work in alphabetic reading, are two ways to characterize the orthography-to-phonology mappings of written languages. These concepts have been applied to Chinese reading research despite important differences across writing systems, with mixed results concerning their relative importance. The present study of covert naming in Chinese is distinctive in testing the ERP effects of regularity and consistency in a fully orthogonal design. We found that consistency, but not regularity, affected the N170, P200 and N400 as well as pronunciation transcription accuracies, demonstrating a more prominent role of consistency than regularity in character naming, consistent with conclusions from English word naming. To capture a generalization across writing systems, we propose mapping congruence as a writing-system-independent way of referring to orthography-to-phonology mappings and illustrate these congruence effects in an interactive framework of character identification.

When dogs meow: An electrophysiological study of lexical-semantic processing in toddlers

The goal of this study was to investigate lexical-semantic processing at an early phase of language development. Adults often communicate with children using infant-directed speech that typically involves lexical and syntactic modifications such as onomatopoeias (Soderstrom, 2007). Here, we asked how and when children start to show an advantage for processing conventional linguistic forms, such as common nouns, and consequently decreasing sensitivity to onomatopoeias. We recorded event-related brain potentials in children of two age groups (16-21 months and 24-31 months) and in an adult control group during the presentation of four conditions in which either common nouns or onomatopoeias were presented auditorily followed by a picture of an either congruent or incongruent object. We focused on the N400 effect, a more negative ERP response to incongruent compared with congruent semantic relations. The younger children showed an N400 effect only for onomatopoeic words, while the older children showed an N400 effect only for common nouns. The adults showed N400 effects for onomatopoeia and nouns. These different N400 effects suggest that onomatopoeia and common nouns are differently organized in children's semantic memory and that the acquisition of linguistic abilities affects and modifies semantic processing of different lexical information.

Age-related differences in the retrieval of phonologically similar words during sentence processing: Evidence from ERPs

We investigated how phonologically similar words are encoded and retrieved from memory during sentence processing across younger and older adults. Critical sentences included two phonologically similar or dissimilar noun phrases (henceforth NPs) followed by a pronoun. We examined brain activity time-locked to the onsets of the second NP, and the pronoun to investigate the encoding and retrieval of the NPs, respectively. Encoding the second NP resulted in smaller N400 amplitudes when the preceding NP was phonologically similar, for both younger and older adults, suggesting age-invariant encoding facilitation with increasing phonological similarity. However, when processing the pronoun, younger adults exhibited greater negativity following phonologically similar NPs, suggesting retrieval difficulty, whereas older adults showed greater negativity for pronouns following dissimilar NPs, suggesting an apparent retrieval facilitation. A post-hoc behavioral experiment suggested that older adults perform shallow processing during retrieval. The results suggest age-related decline in retrieval, but not encoding, of phonological information.

Not Just a Pot: Visual Episodic Memory in Cannabis Users and Polydrug Cannabis Users: ROC and ERP Preliminary Investigation

Background While research has consistently identified an association between long-term cannabis use and memory impairments, few studies have examined this relationship in a polydrug context (i.e., when combining cannabis with other substances). Aims: In this preliminary study, we used event-related potentials to examine the recognition process in a visual episodic memory task in cannabis users (CU) and cannabis polydrug users (PU). We hypothesized that CU and PU will have both-behavioral and psychophysiological-indicators of memory processes affected, compared to matched non-using controls with the PU expressing more severe changes. Methods 29 non-using controls (CG), 24 CU and 27 PU were enrolled into the study. All participants completed a visual learning recognition task while brain electrical activity was recorded. Event-related potentials were calculated for familiar (old) and new images from a signal recorded during a subsequent recognition test. We used receiver operating characteristic curves for behavioral data analysis. Results The groups did not differ in memory performance based on receiver operating characteristic method in accuracy and discriminability indicators nor mean reaction times for old/new images. The frontal old/new effect expected from prior research was observed for all participants, while a parietal old/new effect was not observed. While, the significant differences in the late parietal component (LPC) amplitude was observed between CG and PU but not between CG and CU nor CU and PU. Linear regression analysis was used to examine the mean amplitude of the LPC component as a predictor of memory performance accuracy indicator. LPC amplitude predicts recognition accuracy only in the CG. Conclusion The results showed alterations in recognition memory processing in CU and PU groups compared to CG, which were not manifested on the behavioral level, and were the most prominent in cannabis polydrug users. We interpret it as a manifestation of the cumulative effect of multiple drug usage in the PU group.

Effects of excessive violent video game playing on verbal memory: an event-related brain potentials study

The goal of the study was to investigate temporal dynamics of excessive violent game playing. We compared behavioral data and event-related potentials (ERPs) of excessive video game players (EVGPs, n = 21) and non-players (NPs, n = 21) using a classical learning, cued recall and recognition paradigm, featuring violent and non-violent words. During the recognition phase, EVGPs performed better for violent words, but worse for non-violent words compared to NPs. Also, EVGPs showed slower reaction times than NPs when responding to new violent words. We found significant group differences in parietal P300 and FN400 amplitudes. The EVGP group showed larger P300 amplitudes for violent words, and more negative FN400 amplitudes for new violent words compared to NPs. The results imply that EVGPs differ from NPs in their cognitive and ERP responses to violent and non-violent verbal stimuli. The cognitive processes of EVGPs are consistent with a model of attention and memory bias rather than with desensitization to violence.

Recallable but not recognizable: The influence of semantic priming in recall paradigms

When people can successfully recall a studied word, they should be able to recognize it as having been studied. In cued-recall paradigms, however, participants sometimes correctly recall words in the presence of strong semantic cues but then fail to recognize those words as actually having been studied. Although the conditions necessary to produce this unusual effect are known, the underlying neural correlates have not been investigated. Across five experiments, involving both behavioral and electrophysiological methods (EEG), we investigated the cognitive and neural processes that underlie recognition failures. Experiments 1 and 2 showed behaviorally that assuming that recalled items can be recognized in cued-recall paradigms is a flawed assumption, because recognition failures occur in the presence of cues, regardless of whether those failures are measured. With event-related potentials (ERPs), Experiments 3 and 4 revealed that successfully recalled words that are recognized are driven by recollection at recall and then by a combination of recollection and familiarity at ensuing recognition. In contrast, recognition failures did not show that memory signature and may instead be driven by semantic priming at recall and followed at recognition stages by negative-going ERP effects consistent with implicit processes, such as repetition fluency. These results demonstrate that recall - long-characterized as predominantly reflecting recollection-based processing in episodic memory - may at times also be served by a confluence of implicit cognitive processes.

Distinct FN400/N400 memory effects for perceptually fluent and disfluent words

Recognition memory studies have shown that increased perceptual fluency results in more "old" responses and, presumably, increases familiarity. However, the exact neural mechanisms of these effects remain unresolved. We conducted two ERP experiments in which participants encoded words and performed a recognition test where fluency was manipulated by changing clarity of test words (half of them were clear or blurry). In the more demanding Experiment 1, we found a reversed effect of fluency on recognition (more hits for blurry words), which was accompanied by larger N400 and LPC old/new effects for blurry words. For high confidence responses, the topography of N400 shifted towards frontal electrodes (the FN400 for blurry words). In the less demanding Experiment 2, no behavioral differences between clear and blurry words were observed. However, there was a discrepancy in the ERP results, with the frontal FN400 for blurry words and the parietal N400 for clear words, suggesting that distinct neural pathways can support familiarity-based recognition for clear and blurry items. In both experiments, early perceptual fluency ERP effects were also observed. The results indicate that both semantic processing and familiarity can be enhanced by perceptual fluency and contribute to recognition judgments, depending on the interpretations of fluency.

The N400 indexes acquisition of novel emotion concepts via conceptual combination

The ability to learn new emotion concepts is adaptive and socially valuable as it communicates culturally held understandings about values, goals, and experiences. Yet, little work has examined the underlying mechanisms that allow for new emotion concepts and words to be integrated into the conceptual system. One such mechanism may be conceptual combination, or the ability to form novel concepts by dynamically combining previously acquired conceptual knowledge. In this study, we used event-related potentials (ERPs) to investigate the electrophysiological correlates of novel emotion concept acquisition via conceptual combination. Participants were briefly trained on 30 novel emotion combinations, each consisting of two English emotion words (the components; e.g., "sadness + fatigue") and a pseudoword (the target; e.g., "despip"). Participants then completed a semantic congruency task while ERPs were recorded. On each trial, two components were presented serially, followed by a target; participants judged whether the target was a valid combination of the preceding components. Targets could be correct or incorrect trained pseudowords, or new untrained pseudowords. Furthermore, components could be presented in reversed order (e.g., "fatigue" then "sadness") or as synonyms (e.g., "exhaustion" for "fatigue"). Consistent with our main hypotheses, we found a main effect of target, such that the correct combinations showed reduced N400 amplitudes when compared to both incorrect and untrained pseudowords. Critically, this effect held regardless of how the preceding components were presented, suggesting deeper semantic learning. These results extend prior findings on conceptual combination and novel word learning, and are congruent with predictive processing accounts of brain function.

Usefulness of familiarity signals during recognition depends on test format: Neurocognitive evidence for a core assumption of the CLS framework

Familiarity-based discrimination between studied items and similar foils in yes/no recognition memory tests is relatively poor. The complementary learning systems (CLS) framework explains this with the small difference in familiarity strength between targets and foils. The framework, however, also predicts that familiarity values of targets and corresponding similar foils are directly comparable - as long as they are presented side by side in a forced-choice corresponding (FCC) test. This is because in each trial, targets tend to be more familiar than their corresponding foils. In contrast, when forced-choice displays contain non-corresponding foils (FCNC) which are similar to other studied items, familiarity values are not directly comparable (as in yes/no-tasks). In a recognition memory task with pictures of objects, we found that the putative ERP correlate of familiarity, the mid-frontal old/new effect for targets vs. foils, was significantly larger in FCC compared to FCNC displays. Moreover, single-trial target-foil amplitude differences predicted the accuracy of the recognition judgment. This study supports the assumption of the CLS framework that the test format can influence the diagnostic reliability of familiarity. Moreover, it implies that the mid-frontal old/new effect does not reflect the difference in the familiarity signal between studied and non-studied items but the task-adequate assessment of this signal.

Electrophysiological correlates of the perceptual fluency effect on recognition memory in different fluency contexts

The present study used event-related potentials (ERPs) to investigate the contribution of perceptual fluency to recognition memory in different fluency contexts. In a recognition memory test with a modified remember-know paradigm, we employed conceptually impoverished items (kaleidoscope images) as stimuli and manipulated the perceptual fluency of recognition test cues through masked repetition priming. There were two fluency context conditions. In the random fluency context (RC) condition, primed and unprimed trials were randomly inter-mixed. In the blocked fluency context (BC) condition, primed and unprimed trials were grouped into blocks. Behavioral results showed that priming elevated the incidence of remember hits and the accuracy of remember judgements in the RC condition; no such effects were evident in the BC condition. In addition, priming effects on reaction times were found only for remember hit responses in the RC condition. The ERP results revealed an early100-200 ms effect related to masked repetition priming, which took the form of greater positivity for primed than unprimed trials. This effect was modulated neither by fluency context or response type. The present findings suggest that perceptual fluency induced by masked repetition priming affects recollection-related memory judgments in a specific fluency context and indicate that relative, rather absolute, fluency plays a critical role in influencing recognition memory judgments.

Part-List Cues Hinder Familiarity but Not Recollection in Item Recognition: Behavioral and Event-Related Potential Evidence

Participants' memory performance is normally poorer when a subset of previously learned items is provided as retrieval cues than none of the retrieval cues is provided. This phenomenon is called the part-list cuing effect, which has been discovered in numerous behavioral studies. However, there is currently no relevant behavioral or event-related potential (ERP) research to investigate whether the forgetting effect caused by part-list cues is more sensitive to recollection or to familiarity. By combining the part-list cuing paradigm with the Remember/Know procedure, we investigated this issue in the present ERP study. Behavioral data showed part-list cuing induced detrimental effect in two aspects: significantly lowered familiarity of the target items and decreased memory discrimination score (P_r score) for "Know" but not for "Remember" items in the part-list cue condition than in the no-part-list cue condition. ERP data revealed that the FN400 old/new effects, which are associated with familiarity, were absent when providing part-list cues, whereas the late positive complex (LPC) old/new effects, which are associated with recollection, were observed comparably in both part-list cue and no-part-list cue conditions. Converging behavioral and ERP results suggested that part-list cues hindered familiarity-based retrieval but not recollection-based retrieval of item recognition. Theoretical implications of the findings for the part-list cuing effect are discussed.

A systematic review of cognitive event-related potentials in mild cognitive impairment and Alzheimer's disease

This systematic review examined whether event-related potentials (ERPs) during higher cognitive processing can detect subtle, early signs of neurodegenerative disease. Original, empirical studies retrieved from PsycINFO and PubMed were reviewed if they analyzed patterns in cognitive ERPs (≥150 ms post-stimulus) differentiating mild cognitive impairment (MCI), Alzheimer's disease (AD), or cognitively intact elders who carry AD risk through the Apolipoprotein-E ε4 allele (ε4+) from healthy older adult controls (HC). The 100 studies meeting inclusion criteria (MCI = 47; AD = 47; ε4+ = 6) analyzed N200, P300, N400, and occasionally, later components. While there was variability across studies, patterns of reduced amplitude and delayed latency were apparent in pathological aging, consistent with AD-related brain atrophy and cognitive impairment. These effects were particularly evident in advanced disease progression (i.e., AD > MCI) and in later ERP components measured during complex tasks. Although ERP studies in intact ε4+ elders are thus far scarce, a similar pattern of delayed latency was notable, along with a contrasting pattern of increased amplitude, consistent with compensatory neural activation. This limited work suggests ERPs might be able to index early neural changes indicative of future cognitive decline in otherwise healthy elders. As ERPs are also accessible and affordable relative to other neuroimaging methods, their addition to cognitive assessment might substantively enhance early identification and characterization of neural dysfunction, allowing opportunity for earlier differential diagnosis and targeting of intervention. To evaluate this possibility there is urgent need for well-powered studies assessing late cognitive ERPs during complex tasks, particularly in healthy elders at risk for cognitive decline.

Neural correlates of the Dunning-Kruger effect

The Dunning-Kruger effect (DKE) is a metacognitive phenomenon of illusory superiority in which individuals who perform poorly on a task believe they performed better than others, yet individuals who performed very well believe they under-performed compared to others. This phenomenon has yet to be directly explored in episodic memory, nor explored for physiological correlates or reaction times. We designed a novel method to elicit the DKE via a test of item recognition while electroencephalography (EEG) was recorded. Throughout the task, participants were asked to estimate the percentile in which they performed compared to others. Results revealed participants in the bottom 25th percentile over-estimated their percentile, while participants in the top 75th percentile under-estimated their percentile, exhibiting the classic DKE. Reaction time measures revealed a condition-by-group interaction whereby over-estimators responded faster than under-estimators when estimating being in the top percentile and responded slower when estimating being in the bottom percentile. Between-group EEG differences were evident between over-estimators and under-estimators during Dunning-Kruger responses, which revealed FN400-like effects of familiarity supporting differences for over-estimators, whereas "old-new" memory event-related potential effects revealed a late parietal component associated with recollection-based processing for under-estimators that was not evident for over-estimators. Findings suggest over- and under-estimators use differing cognitive processes when assessing their performance, such that under-estimators may rely on recollection during memory while over-estimators may draw upon excess familiarity when over-estimating their performance. Episodic memory thus appears to play a contributory role in metacognitive judgements of illusory superiority.

FN400 and LPC Responses to Different Degrees of Sensory Involvement: A Study of Sentence Comprehension

The current study tested the likely effect of sensory involvement on the FN400 and late positive complex (LPC) responses to semantic and pragmatic comprehension of English sentences. Fifteen English language learners took part in the event-related potential (ERP) experiment and determined the acceptability of 432 sentences under congruent, semantically incongruent, and pragmatically incongruent conditions. Prior to the ERP recording, the subjects received different sensory instructions for six vocabulary items about which they had no previous knowledge. No sensory instruction was given for three extra words, and these served as the control group. The behavioral data corroborated that integration of more senses in instruction improved learners' pragmatic comprehension. The ERP data revealed that full sensory involvement (involvement) reduced the FN400 amplitude, facilitating real world knowledge retrieval and pragmatic comprehension. The LPC responses to semantic comprehension showed that learners reanalyzed the sentences instructed through limited sensory involvement (exvolvement) more deeply.

The neurocognitive basis of metamemory: Using the N400 to study the contribution of fluency to judgments of learning

Metamemory is crucial for monitoring, evaluating, and optimizing memory performance. The basis of metamemory, however, is a matter of considerable debate. In the present study, we examined the contribution of processing fluency-the ease of processing information during learning-to metamemory judgments. We recorded event-related potentials (ERPs) while participants studied related and unrelated word pairs across two study-test cycles in a judgment of learning (JOL) task. In the first study-test cycle, related pairs were associated with better cued recall, higher JOLs, and a reduced N400 amplitude than unrelated pairs. Crucially, between- and within subject correlational analyses indicated that reduced N400 amplitudes, indexing more fluent processing, were associated with higher JOLs. Furthermore, single-trial N400 mediated a small but significant portion of the relatedness effect on JOLs. In the second study-test cycle, relatedness still increased recall and JOLs. However, related and unrelated pairs did not differ in N400 amplitude. Rather, unrelated pairs elicited a parietal positivity in a later time window that partially mediated the relatedness effect on JOLs. Together, these results suggest that processing fluency, indexed by the N400, contributes to the relatedness effect on JOLs when novel word pairs are learned, but not when previously studied pairs are relearned. Our results also imply that aspects of fluency not captured by the N400 and/or explicit beliefs about memory contribute to JOLs. This study demonstrates the utility of ERPs in gaining new insights into the neurocognitive mechanisms of metamemory.

Neurophysiological evidence for the retrieval practice effect under emotional context

Testing has been demonstrated to enhance memory retention compared to restudy, which is known as the retrieval practice effect. Although much evidence has shown that emotional arousal has an impact on memory retention, little is known about how emotional arousal would influence the retrieval practice effect. To answer this question, the current study used emotional pictures as a context to induce the emotional arousal for restudy or retrieval practice. A Remember/Know paradigm was used in the final test with EEG recordings to examine how the impact of emotional arousal on retrieval practice effect would be reflected in familiarity or recollection. Behavioral results showed that the remembrance was enhanced by the retrieval practice compared to the restudy under both neutral and emotional contexts. Consistently, a parietal old/new effect from 500 to 800 ms was only found for the retrieval practice but not for the restudy condition under both neutral and emotional contexts. These findings indicated that retrieval practice could enhance later recollection when compared to restudy irrespective of emotional or neutral contexts.

On the role of retrieval processes in the survival processing effect: Evidence from ROC and ERP analyses

Memory is enhanced for words encoded in the context of an imagined survival scenario, an effect modulated by word imageability or concreteness. However, the mechanisms underlying this "survival processing effect" are still controversial. To address this issue, we used receiver operating characteristic (ROC) curves and event-related potentials (ERPs) to examine the recognition retrieval processes associated with words previously encoded in either a survival or a control scenario. More specifically, we investigated how recollection- and familiarity-based retrieval are influenced by survival processing of high- and low-imageability words. Participants incidentally encoded words and then completed a surprise recognition test while their EEG was recorded. The encoding of concrete, high-imageability words in a survival context lead to improved recognition memory compared to the control context, and this improvement was associated with an increase in both the ROC and ERP measures of recollection-based memory retrieval. Survival processing was also associated with an increase in the ERP familiarity signal for these words, but the ROC analysis indicated that recognition judgments relied upon recollection rather than familiarity. These findings provide evidence that survival processing increases elaboration during encoding, leading to greater recollection at retrieval and, in turn, enhanced memory.

Late positive complex in event-related potentials tracks memory signals when they are decision relevant

The Late Positive Complex (LPC) is an Event-Related Potential (ERP) consistently observed in recognition-memory paradigms. In the present study, we investigated whether the LPC tracks the strength of multiple types of memory signals, and whether it does so in a decision dependent manner. For this purpose, we employed judgements of cumulative lifetime exposure to object concepts, and judgements of cumulative recent exposure (i.e., frequency judgements) in a study-test paradigm. A comparison of ERP signatures in relation to degree of prior exposure across the two memory tasks and the study phase revealed that the LPC tracks both types of memory signals, but only when they are relevant to the decision at hand. Another ERP component previously implicated in recognition memory, the FN400, showed a distinct pattern of activity across conditions that differed from the LPC; it tracked only recent exposure in a decision-dependent manner. Another similar ERP component typically linked to conceptual processing in past work, the N400, was sensitive to degree of recent and lifetime exposure, but it did not track them in a decision dependent manner. Finally, source localization analyses pointed to a potential source of the LPC in left ventral lateral parietal cortex, which also showed the decision-dependent effect. The current findings highlight the role of decision making in ERP markers of prior exposure in tasks other than those typically used in studies of recognition memory, and provides an initial link between the LPC and the previously suggested role of ventral lateral parietal cortex in memory judgements.

The Influence of Hierarchical Masks on Masked Repetition Priming: Evidence From Event-Related Potential Investigation

The discussion about relationship between prime and target has contributed to the mechanism of priming effect and object recognition. Nevertheless, the role of relationship between mask and target in those cognitive processes remains unquestioned. In the present study, we aim to investigate how mask-target hierarchical relationship may affect word priming and familiarity, by using the masked repetition paradigm and manipulating three hierarchical relationship between mask and target. It is hypothesized that a closer hierarchical relationship between mask and target is associated with a higher mask target similarity, and thereby it leads to a worse recognition performance. Our behavioral results do not support this hypothesis by showing no effect of mask target hierarchical relationship on response time (RT) and accuracy. Event-related potentials (ERPs) indicated that highly similar mask-target triggered (i.e., the subordinate-subordinate-subordinate trials) larger N1 amplitudes, suggesting that it requires more cognitive resource to discriminate the stimuli. In addition, trials with highly similar mask-target hierarchical relationship induced smaller P2 (150–250 ms) and larger mid-frontal FN400 amplitudes than do trials with low mask-target similarity (i.e., the subordinate-basic-subordinate and the subordinate-superordinate-subordinate trials). Our results suggested that the similarity between mask and target may impede conceptual fluency to reduce word priming and familiarity effect.

Briefly Flashed Scenes Can Be Stored in Long-Term Memory

The capacity of human memory is impressive. Previous reports have shown that when asked to memorize images, participants can recognize several thousands of visual objects in great details even with a single viewing of a few seconds per image. In this experiment, we tested recognition performance for natural scenes that participants saw for 20 ms only once (untrained group) or 22 times over many days (trained group) in an unrelated task. 400 images (200 previously viewed and 200 novel images) were flashed one at a time and participants were asked to lift their finger from a pad whenever they thought they had already seen the image (go/no-go paradigm). Compared to previous reports of excellent recognition performance with only single presentations of a few seconds, untrained participants were able to recognize only 64% of the 200 images they had seen few minutes before. On the other hand, trained participants, who had processed the flashed images (20 ms) several times, could correctly recognize 89% of them. EEG recordings confirmed these behavioral results. As early as 230 ms after stimulus onset, a significant event-related-potential (ERP) difference between familiar and new images was observed for the trained but not for the untrained group. These results show that briefly flashed unmasked scenes can be incidentally stored in long-term memory when repeated.

Brain Signatures of New (Pseudo-) Words: Visual Repetition in Associative and Non-associative Contexts

The contribution of two different training contexts to online, gradual lexical acquisition was investigated by event-related potentials (ERPs) elicited by new, word-like stimuli. Pseudowords were repeatedly preceded by a picture representing a well-known object (semantic-associative training context) or by a hash mark (non-associative training context). The two training styles revealed differential effects of repetition in both behavioral and ERPs data. Repetition of pseudowords not associated with any stimulus gradually enhanced the late positive component (LPC) as well as speeded lexical categorization of these stimuli, suggesting the formation of episodic memory traces. However, repetition under the semantic-associative context caused higher reduction in N400 component and categorization latencies. This result suggests the facilitation in the lexico-semantic processing of pseudowords as a consequence of their progressive associations to picture-concepts, going beyond the visual memory trace that is generated under the non-associative context.

On the sensitivity of event-related fields to recollection and familiarity

The sensitivity of event-related potentials (ERPs) to the processes of recollection and familiarity has been explored extensively, and ERPs have been used subsequently to infer the contributions these processes make to memory judgments under a range of different circumstances. It has also been shown that event-related fields (ERFs, the magnetic counterparts of ERPs) are sensitive to memory retrieval processes. The links between ERFs, recollection and familiarity are, however, established only weakly. In this experiment, the sensitivity of ERFs to these processes was investigated in a paradigm used previously with ERPs. An early frontally distributed modulation varied with memory confidence in a way that aligns it with the process of familiarity, while a later parietally distributed modulation tracked subjective claims of recollection in a way that aligns it with this process. These data points strengthen the argument for employing ERFs to assess the contributions these processes can make to memory judgments, as well as for investigating the nature of the processes themselves.

Brain Responses at Encoding Predict Limited Verbal Memory Retrieval by Persons with Schizophrenia

Objective

Special attention has been given to verbal memory deficits in schizophrenia because they are apparent in healthy biological relatives of affected individuals, indicating a link to genetic risk for the disorder. Despite a growing consensus that encoding abnormalities contribute to poor verbal memory in the disorder, few studies have directly examined how neural responses during encoding contribute to later memory performance.

Method

We evaluated event-related potentials (ERPs) during encoding of verbal material by patients with schizophrenia, healthy first-degree biological relatives of patients, and healthy controls. The extent to which N1, N400, and anterior and parietal Late Positive Components (LPCs) explained encoding accuracy and later memory of material was investigated.

Results

Encoding accuracy was associated with asymmetry in anterior LPCs toward right frontal brain regions and was most evident in relatives. N1 was abnormal at encoding in schizophrenia and differentially accounted for later memory performance. In controls better recall of verbal material was predicted by a larger early occipital (N1) encoding response; however, in patients with schizophrenia smaller N1 encoding responses were related to better recall. Interestingly, better recognition of verbal material across groups was also predicted by smaller N1 amplitudes during encoding of word stimuli.

Conclusion

Separable patterns of electrophysiological response during encoding appear to differentially support recall and recognition of material from memory. Similar patterns of electrophysiological response across patient and relative groups suggest that those who carry genetic liability for schizophrenia share deviations in the neural activity related to encoding of material into episodic memory.

The impact of perceptual changes to studied items on ERP correlates of familiarity and recollection is subject to hemispheric asymmetries

It is still unclear which role the right hemisphere (RH) preference for perceptually specific and the left hemisphere (LH) bias towards abstract memory representations play at the level of episodic memory retrieval. When stimulus characteristics hampered the retrieval of abstract memory representations, these hemispheric asymmetries have previously only modulated event-related potential (ERP) correlates of recollection (late positive complex, LPC), but not of familiarity (FN400). In the present experiment, we used stimuli which facilitated the retrieval of abstract memory representations. With the divided visual field technique, new items, identical repetitions and color-modified versions of incidentally studied object pictures were presented in either the right (RVF) or the left visual field (LVF). Participants performed a memory inclusion task, in which they had to categorize both identically repeated and color-modified study items as 'old'. Only ERP, but not behavioral data showed hemispheric asymmetries: Compared to identical repetitions, FN400 and LPC old/new effects for color-modified items were equivalent with RVF/LH presentation, but reduced with LVF/RH presentation. By promoting the use of abstract stimulus information for memory retrieval, we were thus able to show that hemispheric asymmetries in accessing abstract or specific memory representations can modulate ERP correlates of familiarity as well as recollection processes.

Neural bases of automaticity

Automaticity allows us to perform tasks in a fast, efficient, and effortless manner after sufficient practice. Theories of automaticity propose that across practice processing transitions from being controlled by working memory to being controlled by long-term memory retrieval. Recent event-related potential (ERP) studies have sought to test this prediction, however, these experiments did not use the canonical paradigms used to study automaticity. Specifically, automaticity is typically studied using practice regimes with consistent mapping between targets and distractors and spaced practice with individual targets, features that these previous studies lacked. The aim of the present work was to examine whether the practice-induced shift from working memory to long-term memory inferred from subjects' ERPs is observed under the conditions in which automaticity is traditionally studied. We found that to be the case in 3 experiments, firmly supporting the predictions of theories. In addition, we found that the temporal distribution of practice (massed vs. spaced) modulates the shape of learning curves. The ERP data revealed that the switch to long-term memory is slower for spaced than massed practice, suggesting that memory systems are used in a strategic manner. This finding provides new constraints for theories of learning and automaticity. (PsycINFO Database Record

A neural signature of food semantics is associated with body-mass index

Visual recognition of objects may rely on different features depending on the category to which they belong. Recognizing natural objects, such as fruits and plants, weighs more on their perceptual attributes, whereas recognizing man-made objects, such as tools or vehicles, weighs more upon the functions and actions they enable. Edible objects are perceptually rich but also prepared for specific functions, therefore it is unclear how perceptual and functional attributes affect their recognition. Two event-related potentials experiments investigated: (i) whether food categorization in the brain is differentially modulated by sensory and functional attributes, depending on whether the food is natural or transformed; (ii) whether these processes are modulated by participants' body mass index. In experiment 1, healthy normal-weight participants were presented with a sentence (prime) and a photograph of a food. Primes described either a sensory feature ('It tastes sweet') or a functional feature ('It is suitable for a wedding party') of the food, while photographs depicted either a natural (e.g., cherry) or a transformed food (e.g., pizza). Prime-feature pairs were either congruent or incongruent. This design aimed at modulating N400-like components elicited by semantic processing. In experiment 1, N400-like amplitude was significantly larger for transformed food than for natural food with sensory primes, and vice versa with functional primes. In experiment 2, underweight and obese women performed the same semantic task. We found that, while the N400-like component in obese participants was modulated by sensory-functional primes only for transformed food, the same modulation was found in underweight participants only for natural food. These findings suggest that the level of food transformation interacts with participants' body mass index in modulating food perception and the underlying brain processing.

Separating Event-related Potential Effects for Conceptual Fluency and Episodic Familiarity

ERP old/new effects have been associated with different subprocesses of episodic recognition memory. The notion that recollection is reflected in the left parietal old/new effect seems to be uncontested. However, an association between episodic familiarity and the mid-frontal old/new effect is not uncontroversial. It has been argued that the mid-frontal old/new effect is functionally equivalent to the N400 and hence merely reflects differences in conceptual fluency between old and new items. Therefore, it is related to episodic familiarity only in situations in which conceptual fluency covaries with familiarity. Alternatively, the old/new effect in this time window reflects an interaction of episodic familiarity and conceptual processing with each making a unique functional contribution. To test this latter account, we manipulated conceptual fluency and episodic familiarity orthogonally in an incidental recognition test: Visually presented old and new words were preceded by either conceptually related or unrelated auditory prime words. If the mid-frontal old/new effect is functionally distinguishable from conceptual priming effects, an ERP contrast reflecting pure priming (correct rejections in the related vs. unrelated condition) and a contrast reflecting priming plus familiarity (hits in the related vs. correct rejections in the unrelated condition) should differ in scalp distribution. As predicted, the pure priming contrast had a right-parietal distribution, as typically observed for the N400 effect, whereas the priming plus familiarity contrast was significantly more frontally accentuated. These findings implicate that old/new effects in this time window are driven by unique functional contributions of episodic familiarity and conceptual processing.

Aging, working memory capacity and the proactive control of recollection: An event-related potential study

The present study investigated the role of working memory capacity (WMC) in the control of recollection in young and older adults. We used electroencephalographic event-related potentials (ERPs) to examine the effects of age and of individual differences in WMC on the ability to prioritize recollection according to current goals. Targets in a recognition exclusion task were words encoded using two alternative decisions. The left parietal ERP old/new effect was used as an electrophysiological index of recollection, and the selectivity of recollection measured in terms of the difference in its magnitude according to whether recognized items were targets or non-targets. Young adults with higher WMC showed greater recollection selectivity than those with lower WMC, while older adults showed nonselective recollection which did not vary with WMC. The data suggest that aging impairs the ability to engage cognitive control effectively to prioritize what will be recollected.

Impact of Semantic Relatedness on Associative Memory: An ERP Study

Encoding and retrieval processes in memory for pairs of pictures are thought to be influenced by inter-item similarity and by features of individual items. Using Event-Related Potentials (ERP), we aimed to identify how these processes impact on both the early mid-frontal FN400 and the Late Positive Component (LPC) potentials during associative retrieval of pictures. Twenty young adults undertook a sham task, using an incidental encoding of semantically related and unrelated pairs of drawings. At test, we conducted a recognition task in which participants were asked to identify target identical pairs of pictures, which could be semantically related or unrelated, among new and rearranged pairs. We observed semantic (related and unrelated pairs) and condition effects (old, rearranged and new pairs) on the early mid-frontal potential. First, a lower amplitude was shown for identical and rearranged semantically related pairs, which might reflect a retrieval process driven by semantic cues. Second, among semantically unrelated pairs, we found a larger negativity for identical pairs, compared to rearranged and new ones, suggesting additional retrieval processing that focuses on associative information. We also observed an LPC old/new effect with a mid-parietal and a right occipito-parietal topography for semantically related and unrelated old pairs, demonstrating a recollection phenomenon irrespective of the degree of association. These findings suggest that associative recognition using visual stimuli begins at early stages of retrieval, and differs according to the degree of semantic relatedness among items. However, either strategy may ultimately lead to recollection processes.

Electrophysiological signals associated with fluency of different levels of processing reveal multiple contributions to recognition memory

Processing fluency appears to influence recognition memory judgements, and the manipulation of fluency, if misattributed to an effect of prior exposure, can result in illusory memory. Although it is well established that fluency induced by masked repetition priming leads to increased familiarity, manipulations of conceptual fluency have produced conflicting results, variously affecting familiarity or recollection. Some recent studies have found that masked conceptual priming increases correct recollection (Taylor & Henson, 2012), and the magnitude of this behavioural effect correlates with analogous fMRI BOLD priming effects in brain regions associated with recollection (Taylor, Buratto, & Henson, 2013). However, the neural correlates and time-courses of masked repetition and conceptual priming were not compared directly in previous studies. The present study used event-related potentials (ERPs) to identify and compare the electrophysiological correlates of masked repetition and conceptual priming and investigate how they contribute to recognition memory. Behavioural results were consistent with previous studies: Repetition primes increased familiarity, whereas conceptual primes increased correct recollection. Masked repetition and conceptual priming also decreased the latency of late parietal component (LPC). Masked repetition priming was associated with an early P200 effect and a later parietal maximum N400 effect, whereas masked conceptual priming was only associated with a central-parietal maximum N400 effect. In addition, the topographic distributions of the N400 repetition priming and conceptual priming effects were different. These results suggest that fluency at different levels of processing is associated with different ERP components, and contributes differentially to subjective recognition memory experiences.

Age effects on associative memory for novel picture pairings

Normal aging is usually accompanied by greater memory decline for associations than for single items. Though associative memory is generally supported by recollection, it has been suggested that familiarity can also contribute to associative memory when stimuli can be unitized and encoded as a single entity. Given that familiarity remains intact during healthy aging, this may be one route to reducing age-related associative deficits. The current study investigated age-related differences in associative memory under conditions that were expected to differentially promote unitization, in this case by manipulating the spatial arrangement of two semantically unrelated objects positioned relative to each other in either spatially implausible or plausible orientations. Event-related potential (ERP) correlates of item and associative memory were recorded whilst younger and older adults were required to discriminate between old, recombined and new pairs of objects. These ERP correlates of item and associative memory did not vary with plausibility, whereas behavioral measures revealed that both associative and item memory were greater for spatially plausible than implausible pair arrangements. Contrary to predictions, older adults were less able to take advantage of this memory benefit than younger participants. Potential reasons for this are considered, and these are informed by those lines of evidence which indicate older participants were less sensitive to the bottom-up spatial manipulation employed here. It is recommended that future strategies for redressing age-related associative deficits should take account of the aging brain's increasing reliance on pre-existing semantic associations.

Format change and semantic relatedness effects on the ERP correlates of recognition: old pairs, new pairs, different stories

In this event-related potential (ERP) study, we investigated the effects of format change and semantic relatedness in a recognition task using pairs composed of a word and a line drawing. The semantic relatedness of the pairs (related: rabbit-carrot; unrelated: duck-artichoke) influenced their associative properties and corresponding distinctiveness, while format change refers to the switching of an item from the verbal form to the line drawing form between study and recognition (e.g., the word "egg" is associated with a drawing of a hen at study, and a line drawing of an egg is associated with the word "hen" at test). Study-test format change thus prevents visual matching while maintaining conceptual matching. While the N300 potential was only modulated by the semantic relatedness of the pair, both factors modulated recognition performance and corresponding ERP old/new effects with larger mid-frontal N400 old/new effect (300-500 ms) and larger parietal old/new effect (500-800 ms) in the same compared to the different-format condition, as well as for related compared to unrelated pairs. Furthermore, the semantic relatedness of correctly recognized old pairs modulated the anterior N400 while it modulated the posterior N400 for correctly rejected pairs. These results suggest that semantic relatedness and familiarity related to the amount of change between study and test present distinct ERP signatures in the N400 window. They suggest also that the distinctiveness and the ease of the retrieval of the pair could be determining for the parietal old/new effect.

Syllabic tone articulation influences the identification and use of words during Chinese sentence reading: Evidence from ERP and eye movement recordings

In two experiments, we examined the contribution of articulation-specific features to visual word recognition during the reading of Chinese. In spoken Standard Chinese, a syllable with a full tone can be tone-neutralized through sound weakening and pitch contour change, and there are two types of two-character compound words with respect to their articulation variation. One type requires articulation of a full tone for each constituent character, and the other requires a full- and a neutral-tone articulation for the first and second characters, respectively. Words of these two types with identical first characters were selected and embedded in sentences. Native speakers of Standard Chinese were recruited to read the sentences. In Experiment 1, the individual words of a sentence were presented serially at a fixed pace while event-related potentials were recorded. This resulted in less-negative N100 and anterior N250 amplitudes and in more-negative N400 amplitudes when targets contained a neutral tone. Complete sentences were visible in Experiment 2, and eye movements were recorded while participants read. Analyses of oculomotor activity revealed shorter viewing durations and fewer refixations on-and fewer regressive saccades to-target words when their second syllable was articulated with a neutral rather than a full tone. Together, the results indicate that readers represent articulation-specific word properties, that these representations are routinely activated early during the silent reading of Chinese sentences, and that the representations are also used during later stages of word processing.

Pupil old/new effects reflect stimulus encoding and decoding in short-term memory

We conducted five pupil old/new experiments to examine whether pupil old/new effects can be linked to familiarity and/or recollection processes of recognition memory. In Experiments 1-3, we elicited robust pupil old/new effects for legal words and pseudowords (Experiment 1), positive and negative words (Experiment 2), and low-frequency and high-frequency words (Experiment 3). Importantly, unlike for old/new effects in ERPs, we failed to find any effects of long-term memory representations on pupil old/new effects. In Experiment 4, using the words and pseudowords from Experiment 1, participants made lexical decisions instead of old/new decisions. Pupil old/new effects were restricted to legal words. Additionally requiring participants to make speeded responses (Experiment 5) led to a complete absence of old/new effects. Taken together, these data suggest that pupil old/new effects do not map onto familiarity and recollection processes of recognition memory. They rather seem to reflect strength of memory traces in short-term memory, with little influence of long-term memory representations. Crucially, weakening the memory trace through manipulations in the experimental task significantly reduces pupil/old new effects.