Publications

Displaying 1 - 14 of 14
  • Bekemeier, N., Brenner, D., Klepp, A., Biermann-Ruben, K., & Indefrey, P. (2019). Electrophysiological correlates of concept type shifts. PLoS One, 14(3): e0212624. doi:10.1371/journal.pone.0212624.

    Abstract

    A recent semantic theory of nominal concepts by Löbner [1] posits that–due to their inherent uniqueness and relationality properties–noun concepts can be classified into four concept types (CTs): sortal, individual, relational, functional. For sortal nouns the default determination is indefinite (a stone), for individual nouns it is definite (the sun), for relational and functional nouns it is possessive (his ear, his father). Incongruent determination leads to a concept type shift: his father (functional concept: unique, relational)–a father (sortal concept: non-unique, non-relational). Behavioral studies on CT shifts have demonstrated a CT congruence effect, with congruent determiners triggering faster lexical decision times on the subsequent noun than incongruent ones [2, 3]. The present ERP study investigated electrophysiological correlates of congruent and incongruent determination in German noun phrases, and specifically, whether the CT congruence effect could be indexed by such classic ERP components as N400, LAN or P600. If incongruent determination affects the lexical retrieval or semantic integration of the noun, it should be reflected in the amplitude of the N400 component. If, however, CT congruence is processed by the same neuronal mechanisms that underlie morphosyntactic processing, incongruent determination should trigger LAN or/and P600. These predictions were tested in two ERP studies. In Experiment 1, participants just listened to noun phrases. In Experiment 2, they performed a wellformedness judgment task. The processing of (in)congruent CTs (his sun vs. the sun) was compared to the processing of morphosyntactic and semantic violations in control conditions. Whereas the control conditions elicited classic electrophysiological violation responses (N400, LAN, & P600), CT-incongruences did not. Instead they showed novel concept-type specific response patterns. The absence of the classic ERP components suggests that CT-incongruent determination is not perceived as a violation of the semantic or morphosyntactic structure of the noun phrase.

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  • Nayernia, L., Van den Vijver, R., & Indefrey, P. (2019). The influence of orthography on phonemic knowledge: An experimental investigation on German and Persian. Journal of Psycholinguistic Research, 48(6), 1391-1406. doi:10.1007/s10936-019-09664-9.

    Abstract

    This study investigated whether the phonological representation of a word is modulated by its orthographic representation in case of a mismatch between the two representations. Such a mismatch is found in Persian, where short vowels are represented phonemically but not orthographically. Persian adult literates, Persian adult illiterates, and German adult literates were presented with two auditory tasks, an AX-discrimination task and a reversal task. We assumed that if orthographic representations influence phonological representations, Persian literates should perform worse than Persian illiterates or German literates on items with short vowels in these tasks. The results of the discrimination tasks showed that Persian literates and illiterates as well as German literates were approximately equally competent in discriminating short vowels in Persian words and pseudowords. Persian literates did not well discriminate German words containing phonemes that differed only in vowel length. German literates performed relatively poorly in discriminating German homographic words that differed only in vowel length. Persian illiterates were unable to perform the reversal task in Persian. The results of the other two participant groups in the reversal task showed the predicted poorer performance of Persian literates on Persian items containing short vowels compared to items containing long vowels only. German literates did not show this effect in German. Our results suggest two distinct effects of orthography on phonemic representations: whereas the lack of orthographic representations seems to affect phonemic awareness, homography seems to affect the discriminability of phonemic representations.
  • Redmann, A., FitzPatrick, I., & Indefrey, P. (2019). The time course of colour congruency effects in picture naming. Acta Psychologica, 196, 96-108. doi:10.1016/j.actpsy.2019.04.005.

    Abstract

    In our interactions with people and objects in the world around us, as well as in communicating our thoughts, we
    rely on the use of conceptual knowledge stored in long-term memory. From a frame-theoretic point of view, a
    concept is represented by a central node and recursive attribute-value structures further specifying the concept.
    The present study explores whether and how the activation of an attribute within a frame might influence access
    to the concept's name in language production, focussing on the colour attribute. Colour has been shown to
    contribute to object recognition, naming, and memory retrieval, and there is evidence that colour plays a different
    role in naming objects that have a typical colour (high colour-diagnostic objects such as tomatoes) than in
    naming objects without a typical colour (low colour-diagnostic objects such as bicycles). We report two behavioural
    experiments designed to reveal potential effects of the activation of an object's typical colour on naming
    the object in a picture-word interference paradigm. This paradigm was used to investigate whether naming is
    facilitated when typical colours are presented alongside the to-be-named picture (e.g., the word “red” superimposed
    on the picture of a tomato), compared to atypical colours (such as “brown”), unrelated adjectives (such
    as “fast”), or random letter strings. To further explore the time course of these potential effects, the words were
    presented at different time points relative to the to-be-named picture (Exp. 1: −400 ms, Exp. 2: −200 ms, 0 ms,
    and+200 ms). By including both high and low colour-diagnostic objects, it was possible to explore whether the
    activation of a colour differentially affects naming of objects that have a strong association with a typical colour.
    The results showed that (pre-)activation of the appropriate colour attribute facilitated naming compared to an
    inappropriate colour. This was only the case for objects closely connected with a typical colour. Consequences of
    these findings for frame-theoretic accounts of conceptual representation are discussed.
  • Weber, K., Christiansen, M., Indefrey, P., & Hagoort, P. (2019). Primed from the start: Syntactic priming during the first days of language learning. Language Learning, 69(1), 198-221. doi:10.1111/lang.12327.

    Abstract

    New linguistic information must be integrated into our existing language system. Using a novel experimental task that incorporates a syntactic priming paradigm into artificial language learning, we investigated how new grammatical regularities and words are learned. This innovation allowed us to control the language input the learner received, while the syntactic priming paradigm provided insight into the nature of the underlying syntactic processing machinery. The results of the present study pointed to facilitatory syntactic processing effects within the first days of learning: Syntactic and lexical priming effects revealed participants’ sensitivity to both novel words and word orders. This suggested that novel syntactic structures and their meaning (form–function mapping) can be acquired rapidly through incidental learning. More generally, our study indicated similar mechanisms for learning and processing in both artificial and natural languages, with implications for the relationship between first and second language learning.
  • Davidson, D., & Indefrey, P. (2011). Error-related activity and correlates of grammatical plasticity. Frontiers in Psychology, 2: 219. doi:10.3389/fpsyg.2011.00219.

    Abstract

    Cognitive control involves not only the ability to manage competing task demands, but also the ability to adapt task performance during learning. This study investigated how violation-, response-, and feedback-related electrophysiological (EEG) activity changes over time during language learning. Twenty-two Dutch learners of German classified short prepositional phrases presented serially as text. The phrases were initially presented without feedback during a pre-test phase, and then with feedback in a training phase on two separate days spaced 1 week apart. The stimuli included grammatically correct phrases, as well as grammatical violations of gender and declension. Without feedback, participants' classification was near chance and did not improve over trials. During training with feedback, behavioral classification improved and violation responses appeared to both types of violation in the form of a P600. Feedback-related negative and positive components were also present from the first day of training. The results show changes in the electrophysiological responses in concert with improving behavioral discrimination, suggesting that the activity is related to grammar learning.
  • Hanulová, J., Davidson, D. J., & Indefrey, P. (2011). Where does the delay in L2 picture naming come from? Psycholinguistic and neurocognitive evidence on second language word production. Language and Cognitive Processes, 26, 902-934. doi:10.1080/01690965.2010.509946.

    Abstract

    Bilinguals are slower when naming a picture in their second language than when naming it in their first language. Although the phenomenon has been frequently replicated, it is not known what causes the delay in the second language. In this article we discuss at what processing stages a delay might arise according to current models of bilingual processing and how the available behavioural and neurocognitive evidence relates to these proposals. Suggested plausible mechanisms, such as frequency or interference effects, are compatible with a naming delay arising at different processing stages. Haemodynamic and electrophysiological data seem to point to a postlexical stage but are still too scarce to support a definite conclusion.
  • Indefrey, P. (2011). Neurobiology of syntax. In P. C. Hogan (Ed.), The Cambridge encyclopedia of the language sciences (pp. 835-838). New York: Cambridge University Press.
  • Indefrey, P. (2011). The spatial and temporal signatures of word production components: a critical update. Frontiers in Psychology, 2(255): 255. doi:10.3389/fpsyg.2011.00255.

    Abstract

    In the first decade of neurocognitive word production research the predominant approach was brain mapping, i.e., investigating the regional cerebral brain activation patterns correlated with word production tasks, such as picture naming and word generation. Indefrey and Levelt (2004) conducted a comprehensive meta-analysis of word production studies that used this approach and combined the resulting spatial information on neural correlates of component processes of word production with information on the time course of word production provided by behavioral and electromagnetic studies. In recent years, neurocognitive word production research has seen a major change toward a hypothesis-testing approach. This approach is characterized by the design of experimental variables modulating single component processes of word production and testing for predicted effects on spatial or temporal neurocognitive signatures of these components. This change was accompanied by the development of a broader spectrum of measurement and analysis techniques. The article reviews the findings of recent studies using the new approach. The time course assumptions of Indefrey and Levelt (2004) have largely been confirmed requiring only minor adaptations. Adaptations of the brain structure/function relationships proposed by Indefrey and Leven (2004) include the precise role of subregions of the left inferior frontal gyrus as well as a probable, yet to date unclear role of the inferior parietal cortex in word production.
  • Van de Meerendonk, N., Indefrey, P., Chwilla, D. J., & Kolk, H. H. (2011). Monitoring in language perception: Electrophysiological and hemodynamic responses to spelling violations. Neuroimage, 54, 2350-2363. doi:10.1016/j.neuroimage.2010.10.022.

    Abstract

    The monitoring theory of language perception proposes that competing representations that are caused by strong expectancy violations can trigger a conflict which elicits reprocessing of the input to check for possible processing errors. This monitoring process is thought to be reflected by the P600 component in the EEG. The present study further investigated this monitoring process by comparing syntactic and spelling violations in an EEG and an fMRI experiment. To assess the effect of conflict strength, misspellings were embedded in sentences that were weakly or strongly predictive of a critical word. In support of the monitoring theory, syntactic and spelling violations elicited similarly distributed P600 effects. Furthermore, the P600 effect was larger to misspellings in the strongly compared to the weakly predictive sentences. The fMRI results showed that both syntactic and spelling violations increased activation in the left inferior frontal gyrus (lIFG), while only the misspellings activated additional areas. Conflict strength did not affect the hemodynamic response to spelling violations. These results extend the idea that the lIFG is involved in implementing cognitive control in the presence of representational conflicts in general to the processing of errors in language perception.
  • Davidson, D. J., & Indefrey, P. (2009). An event-related potential study on changes of violation and error responses during morphosyntactic learning. Journal of Cognitive Neuroscience, 21(3), 433-446. Retrieved from http://www.mitpressjournals.org/doi/pdf/10.1162/jocn.2008.21031.

    Abstract

    Based on recent findings showing electrophysiological changes in adult language learners after relatively short periods of training, we hypothesized that adult Dutch learners of German would show responses to German gender and adjective declension violations after brief instruction. Adjective declension in German differs from previously studied morphosyntactic regularities in that the required suffixes depend not only on the syntactic case, gender, and number features to be expressed, but also on whether or not these features are already expressed on linearly preceding elements in the noun phrase. Violation phrases and matched controls were presented over three test phases (pretest and training on the first day, and a posttest one week later). During the pretest, no electrophysiological differences were observed between violation and control conditions, and participants’ classification performance was near chance. During the training and posttest phases, classification improved, and there was a P600-like violation response to declension but not gender violations. An error-related response during training was associated with improvement in grammatical discrimination from pretest to posttest. The results show that rapid changes in neuronal responses can be observed in adult learners of a complex morphosyntactic rule, and also that error-related electrophysiological responses may relate to grammar acquisition.
  • Davidson, D. J., & Indefrey, P. (2009). Plasticity of grammatical recursion in German learners of Dutch. Language and Cognitive Processes, 24, 1335-1369. doi:10.1080/01690960902981883.

    Abstract

    Previous studies have examined cross-serial and embedded complement clauses in West Germanic in order to distinguish between different types of working memory models of human sentence processing, as well as different formal language models. Here, adult plasticity in the use of these constructions is investigated by examining the response of German-speaking learners of Dutch using magnetoencephalography (MEG). In three experimental sessions spanning their initial acquisition of Dutch, participants performed a sentence-scene matching task with Dutch sentences including two different verb constituent orders (Dutch verb order, German verb order), and in addition rated similar constructions in a separate rating task. The average planar gradient of the evoked field to the initial verb within the cluster revealed a larger evoked response for the German order relative to the Dutch order between 0.2 to 0.4 s over frontal sensors after 2 weeks, but not initially. The rating data showed that constructions consistent with Dutch grammar, but inconsistent with the German grammar were initially rated as unacceptable, but this preference reversed after 3 months. The behavioural and electrophysiological results suggest that cortical responses to verb order preferences in complement clauses can change within 3 months after the onset of adult language learning, implying that this aspect of grammatical processing remains plastic into adulthood.
  • Gullberg, M., Indefrey, P., & Muysken, P. (2009). Research techniques for the study of code-switching. In B. E. Bullock, & J. A. Toribio (Eds.), The Cambridge handbook on linguistic code-switching (pp. 21-39). Cambridge: Cambridge University Press.

    Abstract

    The aim of this chapter is to provide researchers with a tool kit of semi-experimental and experimental techniques for studying code-switching. It presents an overview of the current off-line and on-line research techniques, ranging from analyses of published bilingual texts of spontaneous conversations, to tightly controlled experiments. A multi-task approach used for studying code-switched sentence production in Papiamento-Dutch bilinguals is also exemplified.
  • Indefrey, P., & Davidson, D. J. (2009). Second language acquisition. In L. R. Squire (Ed.), Encyclopedia of neuroscience (pp. 517-523). London: Academic Press.

    Abstract

    This article reviews neurocognitive evidence on second language (L2) processing at speech sound, word, and sentence levels. Hemodynamic (functional magnetic resonance imaging and positron emission tomography) data suggest that L2s are implemented in the same brain structures as the native language but with quantitative differences in the strength of activation that are modulated by age of L2 acquisition and L2 proficiency. Electrophysiological data show a more complex pattern of first and L2 similarities and differences, providing some, although not conclusive, evidence for qualitative differences between L1 and L2 syntactic processing.
  • Weber, K., & Indefrey, P. (2009). Syntactic priming in German–English bilinguals during sentence comprehension. Neuroimage, 46, 1164-1172. doi:10.1016/j.neuroimage.2009.03.040.

    Abstract

    A longstanding question in bilingualism is whether syntactic information is shared between the two language processing systems. We used an fMRI repetition suppression paradigm to investigate syntactic priming in reading comprehension in German–English late-acquisition bilinguals. In comparison to conventional subtraction analyses in bilingual experiments, repetition suppression has the advantage of being able to detect neuronal populations that are sensitive to properties that are shared by consecutive stimuli. In this study, we manipulated the syntactic structure between prime and target sentences. A sentence with a passive sentence structure in English was preceded either by a passive or by an active sentence in English or German. We looked for repetition suppression effects in left inferior frontal, left precentral and left middle temporal regions of interest. These regions were defined by a contrast of all non-target sentences in German and English versus the baseline of sentence-format consonant strings. We found decreases in activity (repetition suppression effects) in these regions of interest following the repetition of syntactic structure from the first to the second language and within the second language.
    Moreover, a separate behavioural experiment using a word-by-word reading paradigm similar to the fMRI experiment showed faster reading times for primed compared to unprimed English target sentences regardless of whether they were preceded by an English or a German sentence of the same structure.
    We conclude that there is interaction between the language processing systems and that at least some syntactic information is shared between a bilingual's languages with similar syntactic structures.

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