Publications

Displaying 1 - 18 of 18
  • 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.
  • FitzPatrick, I., & Indefrey, P. (2010). Lexical competition in nonnative speech comprehension. Journal of Cognitive Neuroscience, 22, 1165-1178. doi:10.1162/jocn.2009.21301.

    Abstract

    Electrophysiological studies consistently find N400 effects of semantic incongruity in nonnative (L2) language comprehension. These N400 effects are often delayed compared with native (L1) comprehension, suggesting that semantic integration in one's second language occurs later than in one's first language. In this study, we investigated whether such a delay could be attributed to (1) intralingual lexical competition and/or (2) interlingual lexical competition. We recorded EEG from Dutch–English bilinguals who listened to English (L2) sentences in which the sentence-final word was (a) semantically fitting and (b) semantically incongruent or semantically incongruent but initially congruent due to sharing initial phonemes with (c) the most probable sentence completion within the L2 or (d) the L1 translation equivalent of the most probable sentence completion. We found an N400 effect in each of the semantically incongruent conditions. This N400 effect was significantly delayed to L2 words but not to L1 translation equivalents that were initially congruent with the sentence context. Taken together, these findings firstly demonstrate that semantic integration in nonnative listening can start based on word initial phonemes (i.e., before a single lexical candidate could have been selected based on the input) and secondly suggest that spuriously elicited L1 lexical candidates are not available for semantic integration in L2 speech comprehension.
  • Gullberg, M., Roberts, L., Dimroth, C., Veroude, K., & Indefrey, P. (2010). Adult language learning after minimal exposure to an unknown natural language. In M. Gullberg, & P. Indefrey (Eds.), The earliest stages of language learning (pp. 5-24). Malden, MA: Wiley-Blackwell.
  • Gullberg, M., Roberts, L., Dimroth, C., Veroude, K., & Indefrey, P. (2010). Adult language learning after minimal exposure to an unknown natural language. Language Learning, 60(S2), 5-24. doi:10.1111/j.1467-9922.2010.00598.x.

    Abstract

    Despite the literature on the role of input in adult second-language (L2) acquisition and on artificial and statistical language learning, surprisingly little is known about how adults break into a new language in the wild. This article reports on a series of behavioral and neuroimaging studies that examine what linguistic information adults can extract from naturalistic but controlled audiovisual input in an unknown and typologically distant L2 after minimal exposure (7–14 min) without instruction or training. We tested the stepwise development of segmental, phonotactic, and lexical knowledge in Dutch adults after minimal exposure to Mandarin Chinese and the role of item frequency, speech-associated gestures, and word length at the earliest stages of learning. In an exploratory neural connectivity study we further examined the neural correlates of word recognition in a new language, identifying brain regions whose connectivity was related to performance both before and after learning. While emphasizing the complexity of the learning task, the results suggest that the adult learning mechanism is more powerful than is normally assumed when faced with small amounts of complex, continuous audiovisual language input.
  • Gullberg, M., & Indefrey, P. (Eds.). (2010). The earliest stages of language learning. Malden, MA: Wiley-Blackwell.

    Abstract

    To understand the nature of language learning, the factors that influence it, and the mechanisms that govern it, it is crucial to study the very earliest stages of language learning. This volume provides a state-of-the art overview of what we know about the cognitive and neurobiological aspects of the adult capacity for language learning. It brings together studies from several fields that examine learning from multiple perspectives using various methods. The papers examine learning after anything from a few minutes to months of language exposure; they target the learning of both artificial and natural languages, involve both explicit and implicit learning, and cover linguistic domains ranging from phonology and semantics to morphosyntax. The findings will inform and extend further studies of language learning in multiple disciplines.
  • Gullberg, M., & Indefrey, P. (Eds.). (2010). The earliest stages of language learning [Special Issue]. Language Learning, 60(Supplement s2).
  • Indefrey, P., & Gullberg, M. (2010). Foreword. Language Learning, 60(S2), v. doi:10.1111/j.1467-9922.2010.00596.x.

    Abstract

    The articles in this volume are the result of an invited conference entitled "The Earliest Stages of Language Learning" held at the Max Planck Institute for Psycholinguistics in Nijmegen, The Netherlands, in October 2009.
  • Indefrey, P., & Gullberg, M. (2010). The earliest stages of language learning: Introduction. Language Learning, 60(S2), 1-4. doi:10.1111/j.1467-9922.2010.00597.x.
  • Indefrey, P., & Gullberg, M. (2010). The earliest stages of language learning: Introduction. In M. Gullberg, & P. Indefrey (Eds.), The earliest stages of language learning (pp. 1-4). Malden, MA: Wiley-Blackwell.
  • Van der Linden, M., Van Turennout, M., & Indefrey, P. (2010). Formation of category representations in superior temporal sulcus. Journal of Cognitive Neuroscience, 22, 1270-1282. doi:10.1162/jocn.2009.21270.

    Abstract

    The human brain contains cortical areas specialized in representing object categories. Visual experience is known to change the responses in these category-selective areas of the brain. However, little is known about how category training specifically affects cortical category selectivity. Here, we investigated the experience-dependent formation of object categories using an fMRI adaptation paradigm. Outside the scanner, subjects were trained to categorize artificial bird types into arbitrary categories (jungle birds and desert birds). After training, neuronal populations in the occipito-temporal cortex, such as the fusiform and the lateral occipital gyrus, were highly sensitive to perceptual stimulus differences. This sensitivity was not present for novel birds, indicating experience-related changes in neuronal representations. Neurons in STS showed category selectivity. A release from adaptation in STS was only observed when two birds in a pair crossed the category boundary. This dissociation could not be explained by perceptual similarities because the physical difference between birds from the same side of the category boundary and between birds from opposite sides of the category boundary was equal. Together, the occipito-temporal cortex and the STS have the properties suitable for a system that can both generalize across stimuli and discriminate between them.
  • Veroude, K., Norris, D. G., Shumskaya, E., Gullberg, M., & Indefrey, P. (2010). Functional connectivity between brain regions involved in learning words of a new language. Brain and Language, 113, 21-27. doi:10.1016/j.bandl.2009.12.005.

    Abstract

    Previous studies have identified several brain regions that appear to be involved in the acquisition of novel word forms. Standard word-by-word presentation is often used although exposure to a new language normally occurs in a natural, real world situation. In the current experiment we investigated naturalistic language exposure and applied a model-free analysis for hemodynamic-response data. Functional connectivity, temporal correlations between hemodynamic activity of different areas, was assessed during rest before and after presentation of a movie of a weather report in Mandarin Chinese to Dutch participants. We hypothesized that learning of novel words might be associated with stronger functional connectivity of regions that are involved in phonological processing. Participants were divided into two groups, learners and non-learners, based on the scores on a post hoc word recognition task. The learners were able to recognize Chinese target words from the weather report, while the non-learners were not. In the first resting state period, before presentation of the movie, stronger functional connectivity was observed for the learners compared to the non-learners between the left supplementary motor area and the left precentral gyrus as well as the left insula and the left rolandic operculum, regions that are important for phonological rehearsal. After exposure to the weather report, functional connectivity between the left and right supramarginal gyrus was stronger for learners than for non-learners. This is consistent with a role of the left supramarginal gyrus in the storage of phonological forms. These results suggest both pre-existing and learning-induced differences between the two groups.
  • Davidson, D. J., & Indefrey, P. (2007). An inverse relation between event-related and time–frequency violation responses in sentence processing. Brain Research, 1158, 81-92. doi:10.1016/j.brainres.2007.04.082.

    Abstract

    The relationship between semantic and grammatical processing in sentence comprehension was investigated by examining event-related potential (ERP) and event-related power changes in response to semantic and grammatical violations. Sentences with semantic, phrase structure, or number violations and matched controls were presented serially (1.25 words/s) to 20 participants while EEG was recorded. Semantic violations were associated with an N400 effect and a theta band increase in power, while grammatical violations were associated with a P600 effect and an alpha/beta band decrease in power. A quartile analysis showed that for both types of violations, larger average violation effects were associated with lower relative amplitudes of oscillatory activity, implying an inverse relation between ERP amplitude and event-related power magnitude change in sentence processing.
  • Haller, S., Klarhoefer, M., Schwarzbach, J., Radue, E. W., & Indefrey, P. (2007). Spatial and temporal analysis of fMRI data on word and sentence reading. European Journal of Neuroscience, 26(7), 2074-2084. doi:10.1111/j.1460-9568.2007.05816.x.

    Abstract

    Written language comprehension at the word and the sentence level was analysed by the combination of spatial and temporal analysis of functional magnetic resonance imaging (fMRI). Spatial analysis was performed via general linear modelling (GLM). Concerning the temporal analysis, local differences in neurovascular coupling may confound a direct comparison of blood oxygenation level-dependent (BOLD) response estimates between regions. To avoid this problem, we parametrically varied linguistic task demands and compared only task-induced within-region BOLD response differences across areas. We reasoned that, in a hierarchical processing system, increasing task demands at lower processing levels induce delayed onset of higher-level processes in corresponding areas. The flow of activation is thus reflected in the size of task-induced delay increases. We estimated BOLD response delay and duration for each voxel and each participant by fitting a model function to the event-related average BOLD response. The GLM showed increasing activations with increasing linguistic demands dominantly in the left inferior frontal gyrus (IFG) and the left superior temporal gyrus (STG). The combination of spatial and temporal analysis allowed a functional differentiation of IFG subregions involved in written language comprehension. Ventral IFG region (BA 47) and STG subserve earlier processing stages than two dorsal IFG regions (BA 44 and 45). This is in accordance with the assumed early lexical semantic and late syntactic processing of these regions and illustrates the complementary information provided by spatial and temporal fMRI data analysis of the same data set.
  • Indefrey, P. (2007). Brain imaging studies of language production. In G. Gaskell (Ed.), Oxford handbook of psycholinguistics (pp. 547-564). Oxford: Oxford University Press.

    Abstract

    Neurocognitive studies of language production have provided sufficient evidence on both the spatial and the temporal patterns of brain activation to allow tentative and in some cases not so tentative conclusions about function-structure relationships. This chapter reports meta-analysis results that identify reliable activation areas for a range of word, sentence, and narrative production tasks both in the native language and a second language. Based on a theoretically motivated analysis of language production tasks it is possible to specify relationships between brain areas and functional processing components of language production that could not have been derived from the data provided by any single task.
  • Joergens, S., Kleiser, R., & Indefrey, P. (2007). Handedness and fMRI-activation patterns in sentence processing. NeuroReport, 18(13), 1339-1343.

    Abstract

    We investigate differences of cerebral activation in 12 right-handed and left-handed participants, respectively, using a sentence-processing task. Functional MRI shows activation of left-frontal and inferior-parietal speech areas (BA 44, BA9, BA 40) in both groups, but a stronger bilateral activation in left-handers. Direct group comparison reveals a stronger activation in right-frontal cortex (BA 47, BA 6) and left cerebellum in left-handers. Laterality indices for the inferior-frontal cortex are less asymmetric in left-handers and are not related to the degree of handedness. Thus, our results show that sentence-processing induced enhanced activation involving a bilateral network in left-handed participants.

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