Cognitive Neuroscience
Goals/Background
We’re fortunate to have access to multiple brain recording tools (EEG, MEG, MRI). But we use those tools sparingly in our research. The best way to understand the brain is not always to observe brain activity — that is only informative if we have a good understanding of what we’re looking at. Effective cognitive neuroscience must be tightly linked to cognitive and computational research, and that is why we do all of them in parallel. Many of the most interesting neuroscience questions about encoding and accessing linguistic information are better investigated using computational modeling approaches for the foreseeable future, and it is not certain that current brain recording tools will be able to contribute to those discussions. I have been using cognitive neuroscience measures since the early 1990s and I have invested much effort in building infrastructure in this area, but I get frustrated by the increasing rush to focus on neuroscience research at the expense of less sexy but cost effective linguistic and cognitive research.
Timing
Much of the time our brain recordings serve as rich, continuous dependent measures, with little concern for neuroanatomy. (The localization of EEG activity is notoriously hard.)
- EEG data provides fine-grained timing information to augment our studies using behavioral measures such as eye-tracking, e.g., Xiang et al. 2009.
- We have contributed to currently lively debates on the cognitive and linguistic processes reflected in well-known EEG components, e.g., Phillips et al. 2005; Gouvea et al. 2010; Lau et al. 2008.
- We’re very interested in what electrophysiology might tell us about syntax-semantics coupling, e.g., Stroud & Phillips 2012; Chow & Phillips 2013.
- A recent focus is on using EEG to probe the time-course of predictive processes, which may be slower than we thought, e.g., Chow et al. 2014.
Neuroanatomy
Neuroanatomical information gets interesting once we have independent evidence on the function of a brain region, and when we also know something about its engagement in a network of regions. Our research on the neuroanatomy of sentence comprehension, led by Ellen Lau, started when we found that the same sentence-level linguistic manipulation elicits activity in quite different brain regions in fMRI and MEG studies. And we independently knew something about region identified by the MEG studies. Getting to the bottom of that puzzle proved far more interesting than we could have imagined. And the detective work relied crucially on Ellen’s cognitive expertise. (Lau, Phillips, & Poeppel, 2008, Nature Reviews Neuroscience.)
Speech Perception
My initial forays into cognitive neuroscience, together with Alec Marantz and David Poeppel, later with Nina Kazanina and Bill Idsardi, focused on speech perception. It is an attractive domain, as the sounds and the perceptual phenomena are relatively well understood, and one can formulate sensible neuroanatomical hypotheses. We combined MEG measures with phonetic/phonological expertise to try to pinpoint specific levels of representation. (Phillips et al. 1995; Phillips et al. 2000; Phillips 2001; Kazanina et al. 2006.)
Publications in Cognitive Neuroscience
including PhD dissertations supervised
Gaston, Phoebe: The role of syntactic prediction in auditory word recognition. University of Maryland, 2020. (Type: PhD Thesis | Abstract | Links | BibTeX)@phdthesis{Gaston2020,Context is widely understood to have some influence on how words are recognized from speech. This dissertation works toward a mechanistic account of how contextual influence occurs, looking deeply at what would seem to be a very simple instance of the problem: what happens when lexical candidates match with auditory input but do not fit with the syntactic context. There is, however, considerable conflict in the existing literature on this question. Using a combination of modelling and experimental work, I investigate both the generation of abstract syntactic predictions from sentence context and the mechanism by which those predictions impact auditory word recognition. In the first part of this dissertation, simulations in jTRACE show that the speed with which changes in lexical activation can be observed in dependent measures should depend on the size and composition of the set of response candidates allowed by the task. These insights inform a new design for the visual world paradigm that ensures that activation can be detected from words that are bad contextual fits, and that facilitatory and inhibitory mechanisms for the syntactic category constraint can be distinguished. This study finds that wrong-category words are activated, a result that is incompatible with an inhibitory syntactic category constraint. I then turn to a different approach to studying lexical activation, using information-theoretic properties of the set of words consistent with the auditory input while neural activity is recorded in MEG. Phoneme surprisal and cohort entropy are evaluated as predictors of the neural response to hearing single words when that response is modeled with temporal response functions. This lays the groundwork for a design that can test different versions of surprisal and entropy, incorporating facilitatory or inhibitory syntactic constraints on lexical activation when the stimuli are short sentences. Finally, I investigate a neural effect in MEG previously thought to reflect syntactic prediction during reading. When lexical predictability is minimized in a new study, there is no longer evidence for structural prediction occurring at the beginning of sentences. This supports the possibility of a tighter link between syntactic and lexical processing. |
Ehrenhofer, Lara; Lau, Ellen; Phillips, Colin: A possible cure for "N400 blindness" to role reversal anomalies in sentence comprehension. In: Forthcoming, (Submitted to Neuropsychologia). (Type: Journal Article | Abstract | Links | BibTeX)@article{Ehrenhofer2019,Human comprehenders rapidly and incrementally integrate linguistic information into predictions about upcoming sentence material. Though rare, cases where information does not immediately impact predictions provide important insights into predictive mechanisms. One wellstudied case is argument role information, which many studies have shown not to immediately impact the N400, an ERP index of prediction, when argument roles on nouns are reversed from their canonical order. In the current study, our aim was to determine whether verbs are necessary for argument role information to rapidly impact prediction. Instead, we serendipitously discovered a set of rolereversal materials that yield the immediate effects of argument roles on predictions that have so far been largely absent in the literature. In a followup experiment, we confirmed our results, again demonstrating an immediate effect of argument role reversal on the N400 in our materials, as well as replicating the absence of N400 effects with the original materials from one of the prior studies. Our results and analyses suggest a new avenue of research into rolereversal anomalies, exploring finegrained nuance in the contextual properties that determine whether argument position has an immediate impact on prediction. |
Chow, Wing Yee; Lau, Ellen; Wang, Suiping; Phillips, Colin: Wait a second! Delayed impact of argument roles on on-line verb prediction. In: Language, Cognition, and Neuroscience, 2018. (Type: Journal Article | Abstract | Links | BibTeX)@article{Chow2018,Comprehenders can use rich contextual information to anticipate upcoming input on the fly, but recent findings suggest that salient information about argument roles may not impact verb prediction. We took advantage of the word order properties of Mandarin Chinese to examine the time course with which argument role information impacts verb prediction. We isolated the contribution of argument role information by manipulating the order of pre-verbal noun phrase arguments while holding lexical information constant, and we examined its effects on accessing the verb in long-term semantic memory by measuring the amplitude of the N400 component. Experiment 1 showed when the verb appeared immediately after its arguments, even strongly constraining argument role information failed to modulate the N400 response to the verb. An N400 effect emerged in Experiment 2 when the verb appeared at a greater delay. Experiment 3 corroborated the contrast between the first two experiments through a within-participants manipulation of the time interval between the arguments and the verb, by varying the position of an adverbial phrase. These results suggest time is a key factor governing how diverse contextual information contributes to predictions. Here argument role information is shown to impact verb prediction, but its effect is not immediate. |
Chow, Wing Yee; Smith, Cybelle; Lau, Ellen; Phillips, Colin: A 'bag-of-arguments' mechanism for initial verb predictions. In: Language, Cognition, and Neuroscience, 2015. (Type: Journal Article | Abstract | Links | BibTeX)@article{Chow2015,Previous studies have shown that comprehenders use rich contextual information to anticipate upcoming input on the fly, but less is known about how comprehenders integrate different sources of information to generate predictions in real time. The current study examines the time course with which the lexical meaning and structural roles of preverbal arguments impact comprehenders’ verb predictions in two event-related potential (ERP) experiments that use the N400 amplitude as a measure of online predictability. Experiment 1 showed that the N400 was sensitive to the cloze probability of a verb when one of the arguments was substituted (e.g., “The superintendent overheard which tenant/realtor the landlord had evicted...”), but not when the roles of the arguments were simply swapped (e.g., “The restaurant owner forgot which customer/waitress the waitress/customer had served ...”). Experiment 2 showed that argument substitution elicited an N400 effect even when the original argument appeared elsewhere in the sentence, indicating that verb predictions are specifically driven by the arguments in the same clause as the verb, rather than by a simple ‘bag-of-words’ mechanism. We propose that initial verb predictions rely on a ‘bag-of- arguments’ mechanism, which specifically relies on the lexical meaning, but not the structural roles, of the arguments in a clause. |
Chow, Wing Yee: The temporal dimension of linguistic prediction. University of Maryland, 2013. (Type: PhD Thesis | Abstract | Links | BibTeX)@phdthesis{Chow2013b,This thesis explores how predictions about upcoming language inputs are computed during real-time language comprehension. Previous research has demonstrated humans’ ability to use rich contextual information to compute linguistic prediction during real-time language comprehension, and it has been widely assumed that contextual information can impact linguistic prediction as soon as it arises in the input. This thesis questions this key assumption and explores how linguistic predictions develop in real- time. I provide event-related potential (ERP) and reading eye-movement (EM) evidence from studies in Mandarin Chinese and English that even prominent and unambiguous information about preverbal arguments’ structural roles cannot immediately impact comprehenders’ verb prediction. I demonstrate that the N400, an ERP response that is modulated by a word’s predictability, becomes sensitive to argument role-reversals only when the time interval for prediction is widened. Further, I provide initial evidence that different sources of contextual information, namely, information about preverbal arguments’ lexical identity vs. their structural roles, may impact linguistic prediction on different time scales. I put forth a research framework that aims to characterize the mental computations underlying linguistic prediction along a temporal dimension. |
Chow, Wing Yee; Phillips, Colin: No semantic illusion in the 'semantic P600' phenomenon: ERP evidence from Mandarin Chinese. In: Brain Research, vol. 1506, pp. 76-93, 2013. (Type: Journal Article | Abstract | Links | BibTeX)@article{Chow2013,Recent observations of unexpected ERP responses to grammatically well-formed role-reversed sentences (the ‘‘Semantic P600’’ phenomenon) have been taken to bear directly on questions about the architecture of the language processing system. This paper evaluates two central pieces of evidence for accounts that propose a syntax-independent semantic composition mechanism, namely the presence of P600 effects and the absence of N400 effects in role-reversed sentences. Experiment 1 examined the relative contribution of the presence of an animacy violation and the semantic relations between words (‘combinability’) to the ERP responses to role-reversed sentences. Experiment 2 examined the ERP responses to role-reversed sentences that are fully animacy-congruous. Results from the two experiments showed that animacy-violated sentences with no plausible non-surface interpretation elicited the same P600 effect as both types of role- reversed sentences; additionally, semantically anomalous target words elicited no N400 effects when they were strongly semantically related to the preceding words, regardless of the presence of animacy violations. Taken together, these findings suggest that the presence of P600s to role- reversed sentences can be attributed to the implausibility of the sentence meaning, and the absence of N400 effects is due to a combination of weak contextual constraints and strong lexical association. The presence of a plausible non-surface interpretation and animacy violations made no unique contribution to the ERP response profiles. Hence, existing ERP findings are compatible with the long-held assumption that online semantic composition is dependent on surface syntax and do not constitute evidence for a syntax-independent semantic composition mechanism. |
Dillon, Brian; Nevins, Andrew; Austin, Alison C.; Phillips, Colin: Syntactic and semantic predictors of tense in Hindi: An ERP investigation. In: Language and Cognitive Processes, vol. 27, no. 3, pp. 313-344, 2012. (Type: Journal Article | Abstract | Links | BibTeX)@article{Dillon2012,Although there is broad agreement that error signals generated during an unexpected linguistic event are reflected in ERP components, there are least two distinct aspects of the process that the ERP signals may reflect. The first is the content of an error, which is the local discrepancy between an observed form and any expectations about upcoming forms, without any reference to why those expectations were held. The second aspect is the cause of an error, which is a context-aware analysis of why the error arose. The current study examines the processes involved in prediction of morphological marking on verbal forms in Hindi, a split ergative language. This is a case where an error with the same local characteristics (illicit morphology) can arise from very different cues: one syntactic in origin (ergative case marking), and the other semantic in origin (a past tense adverbial). Results suggest that the parser indeed tracks the cause in addition to the content of errors. Despite the fact that the critical manipulation of verb marking was identical across cue types, the nature of the cue led to distinct patterns of ERPs in response to anomalous verbal morphology. When verbal morphology was predicted based upon semantic cues, an incorrect future tense form elicited an early negativity in the 200-400 ms interval with a posterior distribution along with a marginally significant P600 effect. In contrast, when verbal morphology was predicted based upon morphosyntactic cues, an incorrect future tense form elicited a right-lateralized anterior negativity (RAN) during the 300-500 ms interval, as well as a P600 response with a broad distribution. |
Stroud, Clare; Phillips, Colin: Examining the evidence for an independent semantic analyzer: An ERP study in Spanish. In: Brain and Language, vol. 120, pp. 107-126, 2012. (Type: Journal Article | Abstract | Links | BibTeX)@article{Stroud2012,Recent ERP findings challenge the widespread assumption that syntactic and semantic processes are tightly coupled. Syntactically well-formed sentences that are semantically anomalous due to thematic mismatches elicit a P600, the component standardly associated with syntactic anomaly. This ‘thematic P600’ effect has been attributed to detection of semantically plausible thematic relations that conflict with the surface syntactic structure of the sentence, implying a processing architecture with an independent semantic analyzer. A key finding is that the P600 is selectively sensitive to the presence of plausible verb-argument relations, and that otherwise an N400 is elicited (The hearty meal was devouring ... vs. The dusty tabletop was devouring ...: Kim & Osterhout, 2005). The current study investigates in Spanish whether the evidence for an independent semantic analyzer is better explained by a standard architecture that rapidly integrates multiple sources of lexical, syntactic, and semantic information. The study manipulated the presence of plausible thematic relations, and varied the choice of auxiliary between passive-biased fue and active-progressive biased estaba. Results show a late positivity that appeared as soon as comprehenders detected an improbable combination of subject animacy, auxiliary bias, or verb voice morphology. This effect appeared at the lexical verb in the fue conditions and at the auxiliary in the estaba conditions. The late positivity elicited by surface thematic anomalies was the same, regardless of the presence of a plausible non-surface interpretation, and no N400 effects were elicited. These findings do not implicate an independent semantic analyzer, and are compatible with standard language processing architectures. |
Dillon, Brian: Structured access in sentence comprehension. University of Maryland, 2011. (Type: PhD Thesis | Abstract | Links | BibTeX)@phdthesis{Dillon2011,This thesis is concerned with the nature of memory access during the construction of long-distance dependencies in online sentence comprehension. In recent years, an intense focus on the computational challenges posed by long-distance dependencies has proven to be illuminating with respect to the characteristics of the architecture of the human sentence processor, suggesting a tight link between general memory access procedures and sentence processing routines (Lewis & Vasishth 2005; Lewis, Vasishth, & Van Dyke 2006; Wagers, Lau & Phillips 2009). The present thesis builds upon this line of research, and its primary aim is to motivate and defend the hypothesis that the parser accesses linguistic memory in an essentially structured fashion for certain long-distance dependencies. In order to make this case, I focus on the processing of reflexive and agreement dependencies, and ask whether or not non- structural information such as morphological features are used to gate memory access during syntactic comprehension. Evidence from eight experiments in a range of methodologies in English and Chinese is brought to bear on this question, providing arguments from interference effects and time-course effects that primarily syntactic information is used to access linguistic memory in the construction of certain long- distance dependencies. The experimental evidence for structured access is compatible with a variety of architectural assumptions about the parser, and I present one implementation of this idea in a parser based on the ACT-R memory architecture. In the context of such a content-addressable model of memory, the claim of structured access is equivalent to the claim that only syntactic cues are used to query memory. I argue that structured access reflects an optimal parsing strategy in the context of a noisy, interference-prone cognitive architecture: abstract structural cues are favored over lexical feature cues for certain structural dependencies in order to minimize memory interference in online processing. |
Gouvea, Ana C; Phillips, Colin; Kazanina, Nina; Poeppel, David: The linguistic processes underlying the P600. In: Language and Cognitive Processes, vol. 25, no. 2, pp. 149–188, 2010. (Type: Journal Article | Abstract | Links | BibTeX)@article{gouvea2010linguistic,The P600 is an event-related brain potential (ERP) typically associated with the processing of grammatical anomalies or incongruities. A similar response has also been observed in fully acceptable long-distance wh-dependencies. Such findings raise the question of whether these ERP responses reflect common underlying processes, and what might be the specific mechanisms that are shared between successful processing of well-formed sentences and the detection and repair of syntactic anomalies. The current study presents a comparison of the ERP responses elicited by syntactic violations, garden path sentences, and long-distance wh-dependencies, using maximally similar materials in a within-subjects design. Results showed that a P600 component was elicited by syntactic violations and garden path sentences, but was less robustly elicited in the long-distance wh-dependency condition. Differences in the scalp topography, onset and duration of the P600 effects are characterised in terms of the syntactic operations involved in building complex syntactic structures, with particular attention to retrieval processes, which control the latency of the P600, and structure building processes, which control its duration and amplitude. |
Lau, Ellen: The predictive nature of language comprehension. University of Maryland, 2009. (Type: PhD Thesis | Abstract | Links | BibTeX)@phdthesis{Lau2009,This dissertation explores the hypothesis that predictive processing—the access and construction of internal representations in advance of the external input that supports them—plays a central role in language comprehension. Linguistic input is frequently noisy, variable, and rapid, but it is also subject to numerous constraints. Predictive processing could be a particularly useful approach in language comprehension, as predictions based on the constraints imposed by the prior context could allow computation to be speeded and noisy input to be disambiguated. Decades of previous research have demonstrated that the broader sentence context has an effect on how new input is processed, but less progress has been made in determining the mechanisms underlying such contextual effects. This dissertation is aimed at advancing this second goal, by using both behavioral and neurophysiological methods to motivate predictive or top-down interpretations of contextual effects and to test particular hypotheses about the nature of the predictive mechanisms in question. The first part of the dissertation focuses on the lexical-semantic predictions made possible by word and sentence contexts. MEG and fMRI experiments, in conjunction with a meta-analysis of the previous neuroimaging literature, support the claim that an ERP effect classically observed in response to contextual manipulations—the N400 effect—reflects facilitation in processing due to lexical- semantic predictions, and that these predictions are realized at least in part through top-down changes in activity in left posterior middle temporal cortex, the cortical region thought to represent lexical-semantic information in long-term memory,. The second part of the dissertation focuses on syntactic predictions. ERP and reaction time data suggest that the syntactic requirements of the prior context impacts processing of the current input very early, and that predicting the syntactic position in which the requirements can be fulfilled may allow the processor to avoid a retrieval mechanism that is prone to similarity-based interference errors. In sum, the results described here are consistent with the hypothesis that a significant amount of language comprehension takes place in advance of the external input, and suggest future avenues of investigation towards understanding the mechanisms that make this possible. |
Xiang, Ming; Dillon, Brian; Phillips, Colin: Illusory licensing effects across dependency types: ERP evidence. In: Brain and Language, vol. 108, no. 1, pp. 40–55, 2009. (Type: Journal Article | Abstract | Links | BibTeX)@article{xiang2009illusory,A number of recent studies have argued that grammatical illusions can arise in the process of completing linguistic dependencies, such that unlicensed material is temporarily treated as licensed, due to the presence of a potential licensor that is semantically appropriate but in a syntactically inappropriate position. A frequently studied case involves illusory licensing of negative polarity items (NPIs) like ever and any, which must appear in the scope (i.e., c command domain) of a negative or similar element. Speakers often show intrusive licensing effects in sentences where an NPI is preceded but not c commanded by a negative element, as in *The restaurants that no newspapers have recommended in their reviews have ever gone out of business. Existing accounts of intrusive licensing have focused on the role of general retrieval processes. In contrast, we propose that intrusive licensing of NPIs reflects semantic/pragmatic processes that are more specific to NPI licensing. As a test of this claim, we present results from an ERP study that presents a structurally matched comparison of intrusive licensing in two types of linguistic dependencies, namely NPI licensing and the binding of reflexive anaphors like himself, herself. In the absence of a potential licensor, both NPIs and reflexives elicit a P600 response, but whereas there is an immediate ERP analog of the intrusion effect for NPI licensing, no such effect is found for reflexive binding. This suggests that the NPI intrusion effect does not reflect general purpose retrieval mechanisms. |
Stroud, Clare: Structural and semantic selectivity in the electrophysiology of sentence comprehension. University of Maryland, 2008. (Type: PhD Thesis | Abstract | Links | BibTeX)@phdthesis{Stroud2008,This dissertation is concerned with whether the sentence processor can compute plausible relations among a cluster of neighboring open class words without taking into account the relationships between these words as dictated by the structure of the sentence. It has been widely assumed that compositional semantics is built on top of syntactic structures (Heim & Kratzer, 1998; Pollard & Sag, 1994). This view has been challenged by recent electrophysiological findings (Kim and Osterhout, 2005; Kuperberg, 2007; van Herten et al., 2005, 2006) that appear to show that semantic composition can proceed independently of syntactic structure. This dissertation investigates whether the evidence for independent semantic composition is as strong and widespread as has been previously claimed. Recent studies have shown that sentences containing a semantically anomalous interpretation but an unambiguous, grammatical structure (e.g., The meal was devouring...) elicit a P600 response, the component classically elicited by syntactic anomalies, rather than an N400, the component typically elicited by semantic anomalies (Kim and Osterhout, 2005). This has been interpreted as evidence that the processor analyzed meal as a good theme for devour, even though this interpretation is not supported by the sentential structure. This led to the claim that semantic composition can proceed independently of syntactic structure. Two event-related potentials (ERP) studies investigated whether the processor exploits prior structural biases and commitments to restrict semantic interpretations to those that are compatible with that expected structure. A further ERP study and a review of relevant studies reveal that in the majority of studies the P600 is not modulated by manipulations of thematic fit or semantic association between the open class words. We argue that a large number of studies that have been taken as evidence for an independent semantic processing stream can be explained as violations of the verb’s requirement that its subject be agentive. A small number of studies in verb- final languages cannot be explained in this way, and may be evidence of independent semantic composition, although further experimental work is needed. We conclude that the evidence for independent semantic composition is not as extensive as was previously thought. |
Lau, Ellen F; Phillips, Colin; Poeppel, David: A cortical network for semantics:(de) constructing the N400. In: Nature Reviews Neuroscience, vol. 9, no. 12, pp. 920–933, 2008. (Type: Journal Article | Abstract | Links | BibTeX)@article{lau2008cortical,Measuring event-related potentials (ERPs) has been fundamental to our understanding of how language is encoded in the brain. One particular ERP response, the N400 response, has been especially influential as an index of lexical and semantic processing. However, there remains a lack of consensus on the interpretation of this component. Resolving this issue has important consequences for neural models of language comprehension. Here we show that evidence bearing on where the N400 response is generated provides key insights into what it reflects. A neuroanatomical model of semantic processing is used as a guide to interpret the pattern of activated regions in functional MRI, magnetoencephalography and intracranial recordings that are associated with contextual semantic manipulations that lead to N400 effects. |
Nevins, Andrew; Dillon, Brian; Malhotra, Shiti; Phillips, Colin: The role of feature-number and feature-type in processing Hindi verb agreement violations. In: Brain Research, vol. 1164, pp. 81–94, 2007. (Type: Journal Article | Abstract | Links | BibTeX)@article{nevins2007role,This article presents studies of Hindi that investigate whether responses to syntactic agreement violations vary as a function of the type and number of incorrect agreement features, using both electrophysiological (ERP) and behavioral measures. Hindi is well suited to investigation of this issue, since verbs in Hindi mark agreement with the person, number, and gender features of the nominative subject noun phrase. In an ERP study evoked responses were recorded for visually presented verbs appearing at the end of a sentence- initial adverbial clause, comparing responses in a grammatically correct condition with four grammatically incorrect conditions that mismatched the correct agreement on different dimensions (Gender, Number, Gender/Number, Person/Gender). A P600 response was elicited in all grammatically incorrect conditions. No amplitude differences were found among the Gender, Number, and combined Gender/Number violations. This suggests that the feature distance between observed and expected word forms at the morphosyntactic level does not impact ERP responses, contrasting with findings on semantic and auditory processing, and suggests that the P600 response to agreement violations is not additive based on the number of mismatching features and does not reflect top-down, predictive mechanisms. A significantly larger P600 response was elicited by the combined Person/ Gender violation, and two different violations involving the Person feature were judged as more severe and recognized more quickly in the behavioral studies. This effect is attributed to the greater salience of the Person feature at multiple levels of representation. |
Kazanina, Nina; Phillips, Colin; Idsardi, William: The influence of meaning on the perception of speech sounds. In: Proceedings of the National Academy of Sciences, vol. 103, no. 30, pp. 11381–11386, 2006. (Type: Journal Article | Abstract | Links | BibTeX)@article{kazanina2006influence,As part of knowledge of language, an adult speaker possesses information on which sounds are used in the language and on the distribution of these sounds in a multidimensional acoustic space. However, a speaker must know not only the sound categories of his language but also the functional significance of these catego- ries, in particular, which sound contrasts are relevant for storing words in memory and which sound contrasts are not. Using magnetoencephalographic brain recordings with speakers of Rus- sian and Korean, we demonstrate that a speaker’s perceptual space, as reflected in early auditory brain responses, is shaped not only by bottom-up analysis of the distribution of sounds in his language but also by more abstract analysis of the functional significance of those sounds. |
Phillips, Colin; Wagers, Matthew: Constituent structure and the binding problem. In: Behavioral and Brain Sciences, vol. 29, no. 01, pp. 81–82, 2006, (Commentary). (Type: Journal Article | Abstract | Links | BibTeX)@article{phillips2006constituent,Van der Velde & de Kamps’ model encodes complex word-to-word relations in sentences, but does not encode the hierarchical constituent structure of sentences, a fundamental property of most accounts of sentence structure. We summarize what is at stake, and suggest two ways of incorporating constituency into the model. |
Phillips, Colin; Kazanina, Nina; Abada, Shani H: ERP effects of the processing of syntactic long-distance dependencies. In: Cognitive Brain Research, vol. 22, no. 3, pp. 407–428, 2005. (Type: Journal Article | Abstract | Links | BibTeX)@article{phillips2005erp,In behavioral studies on sentence comprehension, much evidence indicates that shorter dependencies are preferred over longer dependencies, and that longer dependencies incur a greater processing cost. However, it remains uncertain which of the various steps involved in the processing of long-distance dependencies is responsible for the increased cost of longer dependencies. Previous sentence comprehension studies using event-related potentials (ERPs) have revealed response components that reflect the construction [J. King, M. Kutas, Who did what and when? Using word- and clause-level ERPs to monitor working memory usage in reading. Journal of Cognitive Neuroscience, 7, (1995) 376–395.] and completion [E. Kaan, A. Harris, E. Gibson, P. Holcomb, The P600 as an index of syntactic integration difficulty. Language and Cognitive Processes, 5, (2000) 159–201.] of long-distance wh-dependencies. This article reports one off-line rating study and one ERP study that manipulated both the presence of wh-dependencies and the length of the dependencies (one clause vs. two clauses), with the aim of clarifying the locus of length-sensitivity and the functional role of associated ERP components. Results of the off- line study confirm that longer wh-dependencies incur greater processing cost. Results of the ERP study indicate that both a sustained anterior negativity that follows the initiation of the wh-dependency and also a late posterior positivity (P600) that marks the completion of the dependency are sensitive to the presence of a wh-dependency, but do not show amplitude variations reflecting the length of the dependency. However, the P600 is delayed when it marks the completion of a longer wh-dependency. This suggests that both the sustained negativity and the P600 reflect length-insensitive aspects of the construction of syntactic dependencies. In addition, an N400 component is elicited in the middle of the two clause wh-dependency, upon encountering a verb with an argument structure that prevents completion of the dependency. |
Phillips, Colin: Electrophysiology in the study of developmental language impairments: Prospects and challenges for a top-down approach. In: Applied Psycholinguistics, vol. 26, no. 01, pp. 79–96, 2005. (Type: Journal Article | Abstract | Links | BibTeX)@article{phillips2005electrophysiology,There is a good deal of interest in the application of neurocognitive techniques to investigate the underpinnings of developmental language impairments (DLIs). Electrophysiological techniques such as electroencephalography and magnetoencephalography offer the promise of the ability to track brain activity with precision in time and space. This article describes a number of findings from studies of normal adults and children that are relevant to neurocognitive studies of developmental language impairments and outlines a series of challenges that should be met in order for electrophysiological measures to realize their promise. |
Phillips, Colin; Sakai, Kuniyoshi L: Language and the brain. In: The McGraw-Hill handbook of science and technology, McGraw-Hill, 2005. (Type: Incollection | Links | BibTeX)@incollection{phillips2005language, |
Phillips, Colin: Levels of representation in the electrophysiology of speech perception. In: Cognitive Science, vol. 25, pp. 711-731, 2001. (Type: Journal Article | Abstract | Links | BibTeX)@article{Phillips2001,Mapping from acoustic signals to lexical representations is a complex process mediated by a number of different levels of representation. This paper reviews properties of the phonetic and phonological levels, and hypotheses about how category structure is represented at each of these levels, and evaluates these hypotheses in light of relevant electrophysiological studies of phonetics and phonology. The paper examines evidence for two alternative views of how infant phonetic represen- tations develop into adult representations, a structure-changing view and a structure-adding view, and suggests that each may be better suited to different kinds of phonetic categories. Electrophysiological results are beginning to provide information about phonological representations, but less is known about how the more abstract representations at this level could be coded in the brain. |
Phillips, Colin; Pellathy, Thomas; Marantz, Alec; Yellin, Elron; Wexler, Kenneth; Poeppel, David; McGinnis, Martha; Roberts, Timothy: Auditory cortex accesses phonological categories: an MEG mismatch study. In: Cognitive Neuroscience, Journal of, vol. 12, no. 6, pp. 1038-1055, 2000. (Type: Journal Article | Abstract | Links | BibTeX)@article{phillips2000auditory,The studies presented here use an adapted oddball paradigm to show evidence that representations of discrete phonological categories are available to the human auditory cortex. Brain activity was recorded using a 37-channel biomagnetometer while eight subjects listened passively to synthetic speech sounds. In the phonological condition, which contrasted stimuli from an acoustic /dñ/±/tñ/ continuum, a magnetic mismatch field (MMF) was elicited in a sequence of stimuli in which phonological categories occurred in a many- to-one ratio, but no acoustic many-to-one ratio was present. In order to isolate the contribution of phonological categories to the MMF responses, the acoustic parameter of voice onset time, which distinguished standard and deviant stimuli, was also varied within the standard and deviant categories. No MMF was elicited in the acoustic condition, in which the acoustic distribution of stimuli was identical to the first experiment, but the many-to-one distribution of phonological categories was removed. The design of these studies makes it possible to demonstrate the all-or-nothing property of phonological category membership. This approach contrasts with a number of previous studies of phonetic perception using the mismatch paradigm, which have demonstrated the graded property of enhanced acoustic discrimination at or near phonetic category boundaries. |
Phillips, Colin; Pellathy, Thomas; Marantz, Alec: Phonological feature representations in auditory cortex. 2000. (Type: Unpublished | Abstract | Links | BibTeX)@unpublished{phillips2000phonological,Although phonemes are the smallest linguistic units that speakers are usually aware of, a good deal of linguistic evidence indicates that sub-phonemic features are the smallest building blocks of language. We present evidence from biomagnetic studies that indicate that representations of discrete phonological feature categories are available to left-hemisphere auditory cortex. Sequences of voiced (/bæ, dæ, gæ/) and voiceless (/pæ, tæ, kæ/) consonants were contrasted in a modified auditory mismatch paradigm. Importantly, although sounds contrasted in a many-to-one ratio at the level of phonological features, the use of 12 acoustically diverse tokens of each category ensured that there was no many-to- one ratio at the acoustic level. Therefore, the fact that an auditory cortex mismatch response was elicited confirms that feature representations are available to this part of the brain. Strikingly, however, the ability of auditory cortex to form a feature-level category from groups of diverse sounds appears to be strongly left- lateralized. |
Sekihara, Kensuke; Poeppel, David; Marantz, Alec; Phillips, Colin; Koizumi, Hideaki; Miyashita, Yasushi: MEG covariance difference analysis: a method to extract target source activities by using task and control measurements. In: IEEE Transactions on Biomedical Engineering, vol. 45, no. 1, pp. 87–97, 1998. (Type: Journal Article | Abstract | Links | BibTeX)@article{sekihara1998meg,A method is proposed for extracting target dipole- source activities from two sets of evoked magnetoencephalo- graphic (MEG) data, one measured using task stimuli and the other using control stimuli. The difference matrix between the two covariance matrices obtained from these two measurements is calculated, and a procedure similar to the MEG-multiple signal classification (MUSIC) algorithm is applied to this difference matrix to extract the target dipole-source configuration. This configuration corresponds to the source-configuration difference between the two measurements. Computer simulation verified the validity of the proposed method. The method was applied to actual evoked-field data obtained from simulated task-and- control experiments. In these measurements, a combination of auditory and somatosensory stimuli was used as the task stimulus and the somatosensory stimulus alone was used as the control stimulus. The proposed covariance difference analysis success- fully extracted the target auditory source and eliminated the disturbance from the somatosensory sources. |
Govindarajan, Krishna K; Phillips, Colin; Poeppel, David; Roberts, Timothy PL; Marantz, Alec: Latency of MEG M100 response indexes first formant frequency. In: The Journal of the Acoustical Society of America, vol. 103, no. 5, pp. 2982–2983, 1998. (Type: Journal Article | Abstract | Links | BibTeX)@article{govindarajan1998latency,Magnetoencephalographic recordings from the auditory cortex of subjects show a close correlation between the timing of the evoked M100 response and the first formant frequency (F1) of vowels and vowel-like stimuli. These results are compatible with evoked magnetic field latencies elicited by tone stimuli, which show 100-300 Hz tones associated with latencies up to 30 ms longer than 500-3000 Hz tones. In Experiment 1, three- formant vowels /u,a,i/ were presented at two fundamental frequencies. The M100 latency was a function of the vowel identity and not F0: M100 was significantly shorter for /a/ than /u/. In Experiment 2, single-formant vowels were covaried with two F0 values. M100 latencies were shorter for /a/ (high F1) than for /u/ (low F1), at both F0 values. In Experiment 3, subjects listened to pure tone complexes with frequencies and amplitudes matching the F0 and F1 energy peaks of the stimuli in Experiment 2. M100 latencies showed the same pattern: latency covaried with the energy peak corresponding to F1, suggesting that the sensitivity to the energy in the F1 range is not specific just to speech stimuli. |
Poeppel, David; Phillips, Colin; Yellin, Elron; Rowley, Howard A; Roberts, Timothy PL; Marantz, Alec: Processing of vowels in supratemporal auditory cortex. In: Neuroscience letters, vol. 221, no. 2, pp. 145–148, 1997. (Type: Journal Article | Abstract | Links | BibTeX)@article{poeppel1997processing,The auditory evoked neuromagnetic fields elicited by synthesized vowels of two different fundamental frequencies F0 were recorded in six subjects over the left and right temporal cortices using a 37-channel biomagnetometer. Single equivalent current dipole modeling of the fields elicited by all vowel types localized activity to a well-circumscribed area in supratemporal auditory cortex in both hemispheres. There were hemisphere asymmetries in the amplitude and latency of the M100 response. We also observed changes in M100 latency related to vowel type, but not to F0. There was no clear effect of vowel type or F0 on dipole localization for the M100, but a possible vowel type by latency interaction. These M100 data provide further evidence that vowels are processed independently of their pitch. |
Poeppel, David; Yellin, Elron; Phillips, Colin; Roberts, Timothy; Rowley, Howard; Wexler, Kenneth; Marantz, Alec: Task-induced asymmetry of the auditory evoked M100 neuromagnetic field elicited by speech sounds. In: Cognitive Brain Research, vol. 4, no. 4, pp. 231–242, 1996. (Type: Journal Article | Abstract | Links | BibTeX)@article{Poeppel1996,The auditory evoked neuromagnetic fields elicited by synthesized speech sounds (consonant-vowel syllables) were recorded in six subjects over the left and right temporal cortices using a 37-channel SQUID-based magnetometer. The latencies and amplitudes of the peaks of the M100 evoked responses were bilaterally symmetric for passively presented stimuli. In contrast, when subjects were asked to discriminate among the same syllabic stimuli, the amplitude of the M100 increased in the left and decreased in the right temporal cortices. Single equivalent current dipole modeling of the activity elicited by all stimulus-types localized to a well-circumscribed area in supratemporal auditory cortex. The results suggest that attentional modulation affects the two supratemporal cortices in a differential manner. Task-conditioned attention to speech sounds is reflected in lateralized supratemporal cortical responses possibly concordant with hemispheric language dominance. |
Phillips, Colin; Marantz, Alec; McGinnis, Martha; Pesetsky, David; Wexler, Kenneth; Yellin, Elron; Poeppel, David; Roberts, Timothy; Rowley, Howard: Brain mechanisms of speech perception: a preliminary report. In: Schütze, Carson; Ganger, Jennifer; Broihier, Kevin (Ed.): vol. Papers on Language Acquisition and Proce, pp. 125–163, vol. 26, 1995. (Type: Book Chapter | Links | BibTeX)@inbook{phillips1995brain, |