Darren Tanner

We investigated the role that semantic constraint and participant control over stimulus presentation have on early stages of visual word recognition. Namely, we tested how the presence of a highly constraining sentential context influences the expectations that readers have during incremental sentence processing. Further, we tested whether allowing participants to self-pace the experiment affected early sensory perceptions of written stimuli. Event-related potentials (ERPs) were recorded in… Show more

We investigated the role that semantic constraint and participant control over stimulus presentation have on early stages of visual word recognition. Namely, we tested how the presence of a highly constraining sentential context influences the expectations that readers have during incremental sentence processing. Further, we tested whether allowing participants to self-pace the experiment affected early sensory perceptions of written stimuli. Event-related potentials (ERPs) were recorded in three experiments. Participants read sentences containing a target word from one of four conditions: 1) the target, spelled as expected; 2) the target with two internal characters transposed; 3) a nonword one vowel different from a target; or 4) an illegal consonant string. In Experiment 1, sentences were minimally constraining up to the target word (average cloze at target word: 0.01); in Experiments 2 and 3, sentences were highly constraining (average cloze at target word: 0.93). In both Experiments 1 and 2, sentences were presented using rapid-serial-visual presentation (RSVP). In Experiment 3, participants saw the same sentences used in Experiment 2 but were allowed to self-pace the presentation of each word in every trial. In Experiments 1 and 2, results showed early neural sensitivity to nonsensical consonant strings only, and only when they appeared within high constraint. In Experiment 3, results showed graded N170 effects to all target words containing unexpected visual information. P600 modulations were observed in all three experiments, indexing the difficulty of processing unexpected orthography, particularly in downstream, integrative processing. Results support a nuanced view of early visual processing, namely one arguing that visual processing is more fine-grained the more control participants have over how they read. Show less

Late second language (L2) learners experience pervasive difficulty mastering grammatical gender, and a comprehensive account of this deficit has yet to emerge. We investigate a previously unexamined aspect of L2 gender use: the time course of lexical feature retrieval. Using event-related potentials (ERPs) with a covert production task, we examined whether L2 gender retrieval is delayed relative to phonology and to the time course of feature retrieval in native speakers for familiar nouns whose… Show more

Late second language (L2) learners experience pervasive difficulty mastering grammatical gender, and a comprehensive account of this deficit has yet to emerge. We investigate a previously unexamined aspect of L2 gender use: the time course of lexical feature retrieval. Using event-related potentials (ERPs) with a covert production task, we examined whether L2 gender retrieval is delayed relative to phonology and to the time course of feature retrieval in native speakers for familiar nouns whose gender participants had strong knowledge of. Results find that L2 gender retrieval is not fundamentally delayed, and that L2 lexical feature retrieval may be more susceptible to top-down influences. These findings place important constraints on accounts of L2 acquisition and processing with respect to how lexical features are represented and retrieved. Our results further suggest that deficits in online L2 gender use may stem from post-retrieval processes and/or retrieval errors rather than inherent delays in gender retrieval. Show less

Many neurocognitive accounts of language processing presume that neural responses detected in grand mean analyses of cortical electrophysiological activity reflect the normative brain response in the population under investigation. However, emerging work now shows that individuals’ brain responses can vary systematically in both the size and type of effect elicited. The present research examined individual differences in neural activity during language comprehension in a large cohort of… Show more

Many neurocognitive accounts of language processing presume that neural responses detected in grand mean analyses of cortical electrophysiological activity reflect the normative brain response in the population under investigation. However, emerging work now shows that individuals’ brain responses can vary systematically in both the size and type of effect elicited. The present research examined individual differences in neural activity during language comprehension in a large cohort of monolingual English speakers (N = 114), a population assumed to be relatively homogenous in terms of linguistic knowledge and processing. Results showed systematic variability in event-related brain potentials (ERPs) elicited by subject-verb agreement anomalies, with brain responses varying on a continuum between N400 and P600 dominant responses. Individuals’ brain response type correlated strongly across these two conditions. Similar variation was also found for ERPs elicited during rapid serial visual presentation and when self-paced ERPs were recorded. Multilevel latent variable regression showed that variation in brain response amplitude and type was not related to individual differences in language experience or verbal working memory capacity, despite high statistical power. These findings indicate that descriptions of processing dynamics predicated solely on grand mean analyses of central tendency can fail to provide an accurate, generalizable account of how processing unfolds in many or most individual members of the population studied. Furthermore, these findings show that systematic individual variation in engagement of neural system supporting grammatical processing is found even in language users at the highest end of the proficiency spectrum and in grammatically simple sentences. This study therefore has implications for studies of language processing in atypical populations. Show less

Some studies have argued that native speakers of tonal languages have been shown to perceive lexical tone continua in a more categorical manner than speakers of non-tonal languages. Among these, Zhang and colleagues (NeuroReport 23 (1): 35-9) conducted an event-related potential (ERP) study using an oddball paradigm showing that native Mandarin speakers exhibit different sensitivity to deviant tones that cross category boundaries compared to deviants that belong to the same category as the… Show more

Some studies have argued that native speakers of tonal languages have been shown to perceive lexical tone continua in a more categorical manner than speakers of non-tonal languages. Among these, Zhang and colleagues (NeuroReport 23 (1): 35-9) conducted an event-related potential (ERP) study using an oddball paradigm showing that native Mandarin speakers exhibit different sensitivity to deviant tones that cross category boundaries compared to deviants that belong to the same category as the standard. Other recent ERP findings examining consonant voicing categories question whether perception is truly categorical. The current study investigated these discrepant findings by replicating and extending the Zhang et al. study. Native Mandarin speakers and naïve English speakers performed an auditory oddball detection test while ERPs were recorded. Naïve English speakers were included to test for language experience effects. We found that Mandarin speakers and English speakers demonstrated qualitatively similar responses, in that both groups showed a larger N2 to the across-category deviant and a larger P3 to the within-category deviant. The N2/P3 pattern also did not differ in scalp topography for the within- versus across-category deviants, as was reported by Zhang et al. Cross-language differences surfaced in behavioral results, where Mandarin speakers showed better discrimination for the across-category deviant, but English speakers showed better discrimination for within-category deviants, though all results were near-ceiling. Our results therefore support models suggesting that listeners remain sensitive to gradient acoustic differences in speech even when they have learned phonological categories along an acoustic dimension. Show less

Recordings of event-related brain potentials (ERPs) provide a rich source of information about the cognitive systems supporting real-time language use. However, the interpretation of ERPs can be complicated by individual differences that aren’t reflected in traditional analyses or visualizations. This is problematic, as failure to recognize important and systematic individual differences has in some cases led to inappropriate interpretations of ERP effects, with neurocognitive models of… Show more

Recordings of event-related brain potentials (ERPs) provide a rich source of information about the cognitive systems supporting real-time language use. However, the interpretation of ERPs can be complicated by individual differences that aren’t reflected in traditional analyses or visualizations. This is problematic, as failure to recognize important and systematic individual differences has in some cases led to inappropriate interpretations of ERP effects, with neurocognitive models of language comprehension sometimes being built on these inappropriate interpretations. In this chapter we review work, largely from our lab, on individual differences in ERP studies of language comprehension and discuss the promise of work on individual differences, as well as the challenges. In some cases individual differences in ERPs manifest themselves quantitatively (i.e., systematic differences in effect amplitudes), but in other more complex cases, qualitatively (i.e., different types of effects in different individuals). We will describe work on individual differences in morphosyntactic and semantic processing in both native and nonnative language processing, as well as multi-modal communication and higher-order pragmatic inferencing. In this last vein we will describe some nascent work done in our lab using unsupervised machine learning algorithms to better understand underlying patterns of qualitative individual differences in the processing of scalar implicatures. We conclude by laying out some challenges and suggestions for future work. Show less

Emojis are ideograms that are becoming ubiquitous in digital communication. However, no research has yet investigated how humans process semantic and pragmatic content of emojis in real time. We investigated neural responses to irony-producing emojis, the question being whether emoji-generated irony is processed similarly to word-generated irony. Previous ERP studies have routinely found P600 effects to verbal irony. Our research sought to identify whether the same neural responses could also… Show more

Emojis are ideograms that are becoming ubiquitous in digital communication. However, no research has yet investigated how humans process semantic and pragmatic content of emojis in real time. We investigated neural responses to irony-producing emojis, the question being whether emoji-generated irony is processed similarly to word-generated irony. Previous ERP studies have routinely found P600 effects to verbal irony. Our research sought to identify whether the same neural responses could also be elicited by emoji-induced irony. In three experiments, participants read sentences that ended in either a congruent, incongruent, or ironic (wink) emoji. Results across all three experiments demonstrated clear P600 effects, the amplitudes of which were correlated with participants’ tendency to treat the emoji as a marker of irony, as indicated by behavioral comprehension question responses. These ironic wink emojis also elicited a strong P200 effect, also found in studies of verbal irony processing. Moreover, unexpected emojis (both mismatch and ironic emoji) also elicited late frontal positivities, which have been implicated processing unpredicted words in context. These results are the first to identify how linguistically-relevant ideograms are processed in real-time at the neural level, and specifically draw parallels between the processing of word- and emoji-induced irony. Show less

An idiom is classically defined as a formulaic sequence whose meaning is comprised of more than the sum of its parts. For this reason, idioms pose a unique problem for models of sentence processing, as researchers must take into account how idioms vary and along what dimensions, as these factors can modulate the ease with which an idiomatic interpretation can be activated. In order to help ensure external validity and comparability across studies, idiom research benefits from the availability… Show more

An idiom is classically defined as a formulaic sequence whose meaning is comprised of more than the sum of its parts. For this reason, idioms pose a unique problem for models of sentence processing, as researchers must take into account how idioms vary and along what dimensions, as these factors can modulate the ease with which an idiomatic interpretation can be activated. In order to help ensure external validity and comparability across studies, idiom research benefits from the availability of publicly available resources reporting ratings from a large number of native speakers. Resources such as the one outlined in the current paper facilitate opportunities for consensus across studies on idiom processing and help to further our goals as a research community. To this end, descriptive norms were obtained for 870 American English idioms from 2,100 participants along five dimensions: familiarity, meaningfulness, literal plausibility, global decomposability, and predictability. Idiom familiarity and meaningfulness strongly correlated with one another, whereas familiarity and meaningfulness were positively correlated with both global decomposability and predictability. Correlations with previous norming studies are also discussed. Show less

We investigated the relative independence of two key processes in language comprehension, as reflected in the P600 ERP component. Numerous studies have linked the P600 to sentence- or message-level reanalysis; however, much research has shown that skilled, cue-based memory retrieval operations are also important to successful language processing. Our goal was to identify whether these cue-based retrieval operations are part of the reanalysis processes indexed by the P600. To this end… Show more

We investigated the relative independence of two key processes in language comprehension, as reflected in the P600 ERP component. Numerous studies have linked the P600 to sentence- or message-level reanalysis; however, much research has shown that skilled, cue-based memory retrieval operations are also important to successful language processing. Our goal was to identify whether these cue-based retrieval operations are part of the reanalysis processes indexed by the P600. To this end, participants read sentences that were either grammatical or ungrammatical via subject-verb agreement violations, and in which there was either no possibility for retrieval interference or there was an attractor noun interfering with the computation of subject-verb agreement (e.g., “The slogan on the political poster(s) was/were …”). A stimulus onset asynchrony manipulation (fast, medium, or slow presentation rate) was designed to modulate participants' ability to engage in reanalysis processes. Results showed a reliable attraction interference effect, indexed by reduced behavioral sensitivity to ungrammaticalities and P600 amplitudes when there was an opportunity for retrieval interference, as well as an effect of presentation rate, with reduced behavioral sensitivity and smaller P600 effects at faster presentation rates. Importantly, there was no interaction between the two, suggesting that retrieval interference and sentence-level reanalysis processes indexed by the P600 can be neurocognitively distinct processes. Show less

Despite early evidence that grammatical gender is retrieved prior to phonology in lexical access, more recent studies demonstrating task effects and non-converging evidence raise doubts about the extent to which this is a general feature of the language production system. We employed the dual-choice go/no-go paradigm with event-related potentials (ERPs) in order to further clarify the time course of retrieval of grammatical gender and phonology. Specifically, we examined how task order… Show more

Despite early evidence that grammatical gender is retrieved prior to phonology in lexical access, more recent studies demonstrating task effects and non-converging evidence raise doubts about the extent to which this is a general feature of the language production system. We employed the dual-choice go/no-go paradigm with event-related potentials (ERPs) in order to further clarify the time course of retrieval of grammatical gender and phonology. Specifically, we examined how task order influences the relative timing with which these features are retrieved. Results find no clear evidence that grammatical gender is retrieved prior to phonology in a serial manner. Instead, the relative timing with which these features are retrieved is subject to task order, suggesting that prior estimates of lexical access obtained with this paradigm may be confounded by task effects. Overall, our result support parallel access models of feature retrieval during lexical access and suggest that attentional biases may modulate retrieval. Show less

Considerable research has investigated how bilinguals produce and comprehend words, focusing mainly on how bilinguals are able to select words from the appropriate language. Less research, however, has investigated whether production and comprehension involve the same underlying mechanisms. The present study explores this issue by examining whether production and comprehension, in the first language (L1) and second language (L2), are similarly influenced by factors relating to language… Show more

Considerable research has investigated how bilinguals produce and comprehend words, focusing mainly on how bilinguals are able to select words from the appropriate language. Less research, however, has investigated whether production and comprehension involve the same underlying mechanisms. The present study explores this issue by examining whether production and comprehension, in the first language (L1) and second language (L2), are similarly influenced by factors relating to language experience, language use, and cognitive functioning. Spanish-English bilinguals living in an English-speaking environment completed a picture naming task and a lexical decision task in their L1 and L2. In addition, participants completed the Operation Span task testing working memory and the Flanker task testing inhibitory control, and completed a language history questionnaire probing their language experience, relative proficiency, and codeswitching behavior. Performance on all tasks was submitted to correlation analyses and the impact of individual difference measures on word production and comprehension was assessed via regression analyses. Results showed that (1) production and comprehension were more closely linked in L1 than in L2; (2) production in L1 and L2 was predicted by language proficiency; and (3) comprehension in L1 and L2 was predicted by working memory. This is the first study to compare lexical processing in production and comprehension in both L1 and L2 and how these processes are influenced by language experience, use, and cognitive factors. Word production and comprehension appear to be more tightly linked in L1 than L2, but seem to rely on different processing mechanisms. Show less

We investigated factors that affect the comprehension of subject–verb agreement in English, using quantification as a window into the relationship between morphosyntactic processes in language production and comprehension. Event-related brain potentials (ERPs) were recorded while participants read sentences with grammatical and ungrammatical verbs, in which the plurality of the subject noun phrase was either doubly marked (via overt plural quantification and morphological marking on the noun)… Show more

We investigated factors that affect the comprehension of subject–verb agreement in English, using quantification as a window into the relationship between morphosyntactic processes in language production and comprehension. Event-related brain potentials (ERPs) were recorded while participants read sentences with grammatical and ungrammatical verbs, in which the plurality of the subject noun phrase was either doubly marked (via overt plural quantification and morphological marking on the noun) or singly marked (via only plural morphology on the noun). Both acceptability judgments and the ERP data showed heightened sensitivity to agreement violations when quantification provided an additional cue to the grammatical number of the subject noun phrase, over and above plural morphology. This is consistent with models of grammatical comprehension that emphasize feature prediction in tandem with cue-based memory retrieval. Our results additionally contrast with those of prior studies that showed no effects of plural quantification on agreement in language production. These findings therefore highlight some nontrivial divergences in the cues and mechanisms supporting morphosyntactic processing in language production and comprehension. Show less

Although it is widely known that high-pass filters can reduce the amplitude of slow ERP components, these filters can also introduce artifactual peaks that lead to incorrect conclusions. To demonstrate this and provide evidence about optimal filter settings, we recorded ERPs in a typical language processing paradigm involving syntactic and semantic violations. Unfiltered results showed standard N400 and P600 effects in the semantic and syntactic violation conditions, respectively. However… Show more

Although it is widely known that high-pass filters can reduce the amplitude of slow ERP components, these filters can also introduce artifactual peaks that lead to incorrect conclusions. To demonstrate this and provide evidence about optimal filter settings, we recorded ERPs in a typical language processing paradigm involving syntactic and semantic violations. Unfiltered results showed standard N400 and P600 effects in the semantic and syntactic violation conditions, respectively. However, high-pass filters with cutoffs at 0.3 Hz and above produced artifactual effects of opposite polarity before the true effect. That is, excessive high-pass filtering introduced a significant N400 effect preceding the P600 in the syntactic condition, and a significant P2 effect preceding the N400 in the semantic condition. Thus, inappropriate use of high-pass filters can lead to false conclusions about which components are influenced by a given manipulation. The present results also lead to practical recommendations for high-pass filter settings that maximize statistical power while minimizing filtering artifacts. Show less

Using event-related potentials (ERPs), we investigated the impact of a range of individual difference measures related to L2 learning on proficient L1 Spanish – L2 English bilinguals’ brain responses during L2 morphosyntactic processing. Although grand mean ERP analyses revealed a biphasic N400–P600 response to English subject–verb agreement violations, subsequent analyses showed that participants’ brain responses varied along a continuum between N400- and P600-dominance. To investigate this… Show more

Using event-related potentials (ERPs), we investigated the impact of a range of individual difference measures related to L2 learning on proficient L1 Spanish – L2 English bilinguals’ brain responses during L2 morphosyntactic processing. Although grand mean ERP analyses revealed a biphasic N400–P600 response to English subject–verb agreement violations, subsequent analyses showed that participants’ brain responses varied along a continuum between N400- and P600-dominance. To investigate this pattern, we introduce two novel ERP measures that independently quantify relative brain response type and overall magnitude. Multivariate analyses revealed that larger overall brain responses were associated with higher L2 proficiency, while relative brain response type (N400 or P600) was predicted by a coalition of variables, most notably learners’ motivation and age of arrival in an L2 environment. Our findings show that aspects of a learner's background can differentially impact a learner's overall sensitivity to L2 morphosyntax and qualitative use of linguistic cues during processing. Show less

We investigated individual differences in the neural substrates of morphosyntactic processing among monolingual English speakers using event-related potentials (ERPs). Although grand-mean analysis showed a biphasic LAN-P600 pattern to grammatical violations, analysis of individuals׳ ERP responses showed that brain responses varied systematically along a continuum between negativity- and positivity-dominant ERP responses across individuals. Moreover, the left hemisphere topography of the… Show more

We investigated individual differences in the neural substrates of morphosyntactic processing among monolingual English speakers using event-related potentials (ERPs). Although grand-mean analysis showed a biphasic LAN-P600 pattern to grammatical violations, analysis of individuals׳ ERP responses showed that brain responses varied systematically along a continuum between negativity- and positivity-dominant ERP responses across individuals. Moreover, the left hemisphere topography of the negativity resulted from component overlap between a centro-parietal N400 in some individuals and a right hemisphere-dominant P600 in others. Our results show that biphasic ERP waveforms do not always reflect separable processing stages within individuals, and moreover, that the LAN can be a variant of the N400. These results show that there are multiple neurocognitive routes to successful grammatical comprehension in language users across the proficiency spectrum. Our results underscore that understanding and quantifying individual differences can provide an important source of evidence about language processing in the general population. Show less

Kara Morgan-Short and I provide an in-depth introduction to methods and applications for using electrical brain activity to understand how people learn and process non-native languages.

Attraction interference in language comprehension and production may be as a result of common or different processes. In the present paper, we investigate attraction interference during language comprehension, focusing on the contexts in which interference arises and the time-course of these effects. Using evidence from event-related brain potentials (ERPs) and sentence judgment times, we show that agreement attraction in comprehension is best explained as morphosyntactic interference during… Show more

Attraction interference in language comprehension and production may be as a result of common or different processes. In the present paper, we investigate attraction interference during language comprehension, focusing on the contexts in which interference arises and the time-course of these effects. Using evidence from event-related brain potentials (ERPs) and sentence judgment times, we show that agreement attraction in comprehension is best explained as morphosyntactic interference during memory retrieval. This stands in contrast to attraction as involving the representation of the subject NP’s root-node number feature, which is a strong contributor to attraction in production. We thus argue that the cognitive antecedents of agreement attraction in comprehension are non-identical with those of attraction in production, and moreover, that attraction in comprehension is primarily a consequence of similarity-based interference in cue-based memory retrieval processes. We suggest that mechanisms responsible for attraction during language comprehension are a subset of those involved in language production. Show less

Here we report findings from a cross-sectional study of morphosyntactic processing in native German speakers and native English speakers enrolled in college-level German courses. Event-related brain potentials were recorded while participants read sentences that were either well-formed or violated German subject–verb agreement. Results showed that grammatical violations elicited large P600 effects in the native Germans and learners enrolled in third-year courses. Grand mean waveforms for… Show more

Here we report findings from a cross-sectional study of morphosyntactic processing in native German speakers and native English speakers enrolled in college-level German courses. Event-related brain potentials were recorded while participants read sentences that were either well-formed or violated German subject–verb agreement. Results showed that grammatical violations elicited large P600 effects in the native Germans and learners enrolled in third-year courses. Grand mean waveforms for learners enrolled in first-year courses showed a biphasic N400–P600 response. However, subsequent correlation analyses revealed that most individuals showed either an N400 or a P600, but not both, and that brain response type was associated with behavioral measures of grammatical sensitivity. These results support models of second language acquisition which implicate qualitative changes in the neural substrates of second language grammar processing associated with learning. Importantly, we show that new insights into L2 learning result when the cross-subject variability is treated as a source of evidence rather than a source of noise. Show less

Although research has consistently shown that a bilingual's two languages interact on multiple levels, it is also well-established that bilinguals can vary considerably in their proficiency in the second language (L2). In this paper we review empirical studies that have examined how differences in L2 proficiency modulate cross-language co-activation and interaction during bilingual lexical processing. We review studies investigating cognate and homograph processing in visual word perception and… Show more

Although research has consistently shown that a bilingual's two languages interact on multiple levels, it is also well-established that bilinguals can vary considerably in their proficiency in the second language (L2). In this paper we review empirical studies that have examined how differences in L2 proficiency modulate cross-language co-activation and interaction during bilingual lexical processing. We review studies investigating cognate and homograph processing in visual word perception and word production, auditory word perception using the visual world paradigm, and cross-language priming, focusing specifically on how differences in proficiency modulate co-activation during lexical access. We further discuss differences in L2 proficiency in relation to immersion and age of L2 acquisition, how differences in L2 proficiency relate to neurocognitive aspects of cognitive control, and how changes in L2 proficiency relative to L1 proficiency may affect lexical processing. Show less

In this article we review several studies investigating the neural correlates of second-language (L2) grammatical learning in the context of novice adult learners progressing through their first year of L2 classroom instruction. The primary goal of these studies was to determine how and when learners incorporate L2 knowledge into their online language processing system. We show that at least some learners progress through discrete stages of grammatical learning during the first year of… Show more

In this article we review several studies investigating the neural correlates of second-language (L2) grammatical learning in the context of novice adult learners progressing through their first year of L2 classroom instruction. The primary goal of these studies was to determine how and when learners incorporate L2 knowledge into their online language processing system. We show that at least some learners progress through discrete stages of grammatical learning during the first year of instruction. These stages are robust across languages, experimental tasks, and levels of language (lexical vs. sentential) and indicate that there is an intermediate stage of learning between no L2 grammatical knowledge and grammaticalization. We also show that although learners’ brain responses are quite variable, this variability is highly systematic and can be used to identify meaningful subgroups of learners. Show less

We investigated interactions between morphological complexity and grammaticality on electrophysiological markers of grammatical processing during reading. Our goal was to determine whether morphological complexity and stimulus grammaticality have independent or additive effects on the P600 event-related potential component. Participants read sentences that were either well-formed or grammatically ill-formed, in which the critical word was either morphologically simple or complex. Results… Show more

We investigated interactions between morphological complexity and grammaticality on electrophysiological markers of grammatical processing during reading. Our goal was to determine whether morphological complexity and stimulus grammaticality have independent or additive effects on the P600 event-related potential component. Participants read sentences that were either well-formed or grammatically ill-formed, in which the critical word was either morphologically simple or complex. Results revealed no effects of complexity for well-formed stimuli, but the P600 amplitude was significantly larger for morphologically complex ungrammatical stimuli than for morphologically simple ungrammatical stimuli. These findings suggest that some previous work may have inadequately characterized factors related to reanalysis during morphosyntactic processing. Our results show that morphological complexity by itself does not elicit P600 effects. However, in ungrammatical circumstances, overt morphology provides a more robust and reliable cue to morphosyntactic relationships than null affixation. Show less