J Open Source Softw
July 2021
Electrical brain activity related to external stimulation and internal mental events can be measured at the scalp as tiny time-varying electric potential waveforms (electroencephalogram; EEG), typically a few tens of microvolts peak to peak (Berger, 1930). Even tinier brain responses, too small to be seen by naked eye in the EEG, can be detected by repeating the stimulation, aligning the EEG recordings to the triggering event and averaging them at each time point (Dawson, 1951, 1954). Under assumptions that the brain response (signal) is the same in each recording and the ongoing background EEG (noise) varies randomly, averaging improves the estimate of the "true" brain response at each time point as the random variation cancels.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
August 2020
In 2005, we reported evidence indicating that upcoming phonological word forms-e.g., vs.
View Article and Find Full Text PDFJ Exp Psychol Learn Mem Cogn
March 2020
In Troyer and Kutas (2018), individual differences in knowledge of the world of Harry Potter (HP) rapidly modulated individuals' average electrical brain potentials to contextually supported words in sentence endings. Using advances in single-trial electroencephalogram analysis, we examined whether this relationship is strictly a result of domain knowledge mediating the proportion of facts each participant knew; we find it is not. Participants read sentences ending in a contextually supported word, reporting online whether they had known each fact.
View Article and Find Full Text PDFDuring incremental language comprehension, the brain activates knowledge of described events, including knowledge elements that constitute semantic anomalies in their linguistic context. The present study investigates hemispheric asymmetries in this process, with the aim of advancing our understanding of the neural basis and functional properties of event knowledge activation during incremental comprehension. In a visual half-field event-related brain potential (ERP) experiment, participants read brief discourses in which the third sentence contained a word that was either highly expected, semantically anomalous but related to the described event (Event-Related), or semantically anomalous but unrelated to the described event (Event-Unrelated).
View Article and Find Full Text PDFLanguage interpretation is often assumed to be incremental. However, our studies of quantifier expressions in isolated sentences found N400 event-related brain potential (ERP) evidence for partial but not full immediate quantifier interpretation (Urbach & Kutas, 2010). Here we tested similar quantifier expressions in pragmatically supporting discourse contexts (//) while participants made plausibility judgments (Experiment 1) or read for comprehension (Experiment 2).
View Article and Find Full Text PDFExtant accounts of visually situated language processing do make general predictions about visual context effects on incremental sentence comprehension; these, however, are not sufficiently detailed to accommodate potentially different visual context effects (such as a scene-sentence mismatch based on actions versus thematic role relations, e.g., (Altmann & Kamide, 2007; Knoeferle & Crocker, 2007; Taylor & Zwaan, 2008; Zwaan & Radvansky, 1998)).
View Article and Find Full Text PDFGrounded cognition theories hold that the neural states involved in experiencing objects play a direct functional role in representing and accessing object knowledge from memory. However, extant data marshaled to support this view are also consistent with an opposing view that perceptuo-motor activations occur only following access to knowledge from amodal memory systems. We provide novel discriminating evidence for the functional involvement of visuo-perceptual states specifically in accessing knowledge about an object's color.
View Article and Find Full Text PDFHow quickly do different kinds of conceptual knowledge become available following visual word perception? Resolving this question will inform neural and computational theories of visual word recognition and semantic memory use. We measured real-time brain activity using event-related brain potentials (ERPs) during a go/nogo task to determine the upper limit by which category-related knowledge (living/nonliving) and action-related knowledge (graspable/ungraspable) must have been accessed to influence a downstream decision process. We find that decision processes can be influenced by the living/nonliving distinction by 160ms after stimulus onset whereas information about (one-hand) graspability is not available before 300ms.
View Article and Find Full Text PDFTo understand how and when object knowledge influences the neural underpinnings of language comprehension and linguistic behavior, it is critical to determine the specific kinds of knowledge that people have. To extend the normative data currently available, we report a relatively more comprehensive set of object attribute rating norms for 559 concrete object nouns, each rated on seven attributes corresponding to sensory and motor modalities-color, motion, sound, smell, taste, graspability, and pain-in addition to familiarity (376 raters, M = 23 raters per item). The mean ratings were subjected to principal-components analysis, revealing two primary dimensions plausibly interpreted as relating to survival.
View Article and Find Full Text PDFRecent research has demonstrated that knowledge of real-world eventsplays an important role inguiding online language comprehension. The present study addresses the scope of event knowledge activation during the course of comprehension, specifically investigating whether activation is limited to those knowledge elements that align with the local linguistic context.The present study addresses this issue by analyzing event-related brain potentials (ERPs) recorded as participants read brief scenariosdescribing typical real-world events.
View Article and Find Full Text PDFPsychophysiology
December 2011
Mass univariate analysis is a relatively new approach for the study of ERPs/ERFs. It consists of many statistical tests and one of several powerful corrections for multiple comparisons. Multiple comparison corrections differ in their power and permissiveness.
View Article and Find Full Text PDFEvent-related potentials (ERPs) and magnetic fields (ERFs) are typically analyzed via ANOVAs on mean activity in a priori windows. Advances in computing power and statistics have produced an alternative, mass univariate analyses consisting of thousands of statistical tests and powerful corrections for multiple comparisons. Such analyses are most useful when one has little a priori knowledge of effect locations or latencies, and for delineating effect boundaries.
View Article and Find Full Text PDFPsychophysiology
September 2011
In 2005, DeLong, Urbach, and Kutas took advantage of the a/an English indefinite article phonological alternation and the sensitivities of the N400 ERP component to show that readers can neurally preactivate individual words of a sentence (including nouns and their prenominal indefinite articles) in a graded fashion with a likelihood estimated from the words' offline probabilities as sentence continuations. Here we report an additional finding from that study: a prolonged ERP frontal positivity to less probable noun continuations. We suggest that this positivity is consistent with hypotheses that additional neural processing may be invoked when highly expected continuations are not encountered in the input and speculate briefly on possible functional correlates.
View Article and Find Full Text PDFThe phonemic restoration effect refers to the tendency for people to hallucinate a phoneme replaced by a non-speech sound (e.g., a tone) in a word.
View Article and Find Full Text PDFTo re-establish picture-sentence verification-discredited possibly for its over-reliance on post-sentence response time (RT) measures-as a task for situated comprehension, we collected event-related brain potentials (ERPs) as participants read a subject-verb-object sentence, and RTs indicating whether or not the verb matched a previously depicted action. For mismatches (vs. matches), speeded RTs were longer, verb N400s over centro-parietal scalp larger, and ERPs to the object noun more negative.
View Article and Find Full Text PDFEvent-related brain potentials were recorded during RSVP reading to test the hypothesis that quantifier expressions are incrementally interpreted fully and immediately. In sentences tapping general knowledge (Farmers grow crops/worms as their primary source of income), Experiment 1 found larger N400s for atypical (worms) than typical objects (crops). Experiment 2 crossed object typicality with non-logical subject-noun phrase quantifiers (most, few).
View Article and Find Full Text PDFRecent proposals regarding the purpose and validity of amplitude normalization by vector scaling including mitigation of baseline and noise problems in between-condition difference analyses are critically evaluated. In so doing, we elaborate on some of the points raised in regarding baselines and noise, especially as these impact amplitude normalization by vector scaling and discuss the motivation for measuring event-related brain potential (ERP) amplitudes relative to a pre-stimulus baseline and the implications of this for certain (but not all) inferences. Throughout, our focus is on the logic of interpreting ERP measurements with an emphasis on the importance of specific assumptions and consideration of what conclusions are and are not supported.
View Article and Find Full Text PDFDespite the numerous examples of anticipatory cognitive processes at micro and macro levels in many animal species, the idea that anticipation of specific words plays an integral role in real-time language processing has been contentious. Here we exploited a phonological regularity of English indefinite articles ('an' precedes nouns beginning with vowel sounds, whereas 'a' precedes nouns beginning with consonant sounds) in combination with event-related brain potential recordings from the human scalp to show that readers' brains can pre-activate individual words in a graded fashion to a degree that can be estimated from the probability that each word is given as a continuation for a sentence fragment offline. These findings are evidence that readers use the words in a sentence (as cues to their world knowledge) to estimate relative likelihoods for upcoming words.
View Article and Find Full Text PDFMemory illusions--vivid experiences of events that never occurred--could result from inaccuracies either in retrieving memories or in initially storing them. In two experiments, people studied lists of associated words that either did or did not induce later illusory (false) memories of associated but nonpresented lure words. The amplitude of the electrical brain activity during study of words (approximately 500-1,300 ms) that were themselves later correctly remembered reliably distinguished list words that led to such illusory memories from those that did not.
View Article and Find Full Text PDFPsychophysiology
November 2002
ERP researchers use differences in scalp distributions to infer differences in spatial configurations of neuroelectric generators. Since McCarthy and Wood (1985) demonstrated that a spatially fixed current source varying only in strength can yield a significant Condition x Electrode interaction in ANOVA, the recommended approach has been to normalize ERP amplitudes, for example, by vector length, prior to testing for interactions. The assumptions of this procedure are examined and it is shown via simulations that this application of vector scaling is both conceptually flawed and unsound in experimental practice.
View Article and Find Full Text PDFIn recognition memory tasks, stimuli can be classified as "old" either on the basis of accurate memory or a bias to respond "old", yet bias has received little attention in the cognitive neuroscience literature. Here we examined the pattern and timing of bias-related effects in event-related brain potentials (ERPs) to determine whether the bias is linked more to memory retrieval or to response verification processes. Participants were divided into a High Bias and a Low Bias group according to their bias to respond "old".
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