Publications

Abstract

Rapid advances over the last decade in DNA sequencing and statistical genetics enable us to investigate the genomic makeup of individuals throughout history. In a recent notable study, Begg et al.1 used Ludwig van Beethoven’s hair strands for genome sequencing and explored genetic predispositions for some of his documented medical issues. Given that it was arguably Beethoven’s skills as a musician and composer that made him an iconic figure in Western culture, we here extend the approach and apply it to musicality. We use this as an example to illustrate the broader challenges of individual-level genetic predictions.

Abstract

In this paper, we report an experiment on the naming of household containers in Dutch and Icelandic carried out as part of the Evolution of Semantic Systems project (EoSS; Majid et al., 2011). This naming experiment allows us to support and elaborate on a hypothesis by Malt et al. (2003) that productive morphology in the naming domain can have an influence on boundary placement within the extensional space. Specifically, we demonstrate that the Dutch diminutive -(t)je favours a cut between small items versus others, whereas Icelandic, which does not use the diminutive in this domain, favours a cut between large items and others. This is not a typological effect, as Dutch and Icelandic are both Germanic languages and both have diminutive morphology available in principle. We find no evidence that the diminutive produces a proliferation of terms and/or fine-grained nesting within the extensional domain. Rather, the Dutch diminutive favours a more even distribution of terms across the space whereas Icelandic favours broad inclusive terms with a number of narrower specialist terms. Further, the extensional space defined by the diminutive is not associated with its own clear prototypical exemplar. Using evidence from compounding and modification, we also consider which semantic features are prominent in differentiating categories within the domain. By far the most prominent in both languages is the inferred contents of the container. Other than contents, however, the languages differ in the range and prominence of features such as intended usage or material of composition. Our results demonstrate that in order to understand the processes that produce semantic divisions of basic object classes, we should consider fine-grained analyses of closely related languages alongside analyses of typologically different languages.

Abstract

Although generally studied in isolation, language and action often co-occur in everyday life. Here we investigated one particular form of simultaneous language and action, namely speech and gestures that speakers use in everyday communication. In a functional magnetic resonance imaging study, we identified the neural networks involved in the integration of semantic information from speech and gestures. Verbal and/or gestural content could be integrated easily or less easily with the content of the preceding part of speech. Premotor areas involved in action observation (Brodmann area [BA] 6) were found to be specifically modulated by action information "mismatching" to a language context. Importantly, an increase in integration load of both verbal and gestural information into prior speech context activated Broca's area and adjacent cortex (BA 45/47). A classical language area, Broca's area, is not only recruited for language-internal processing but also when action observation is integrated with speech. These findings provide direct evidence that action and language processing share a high-level neural integration system.

Abstract

Co-speech gestures embody a form of manual action that is tightly coupled to the language system. As such, the co-occurrence of speech and co-speech gestures is an excellent example of the interplay between language and action. There are, however, other ways in which language and action can be thought of as closely related. In this paper we will give an overview of studies in cognitive neuroscience that examine the neural underpinnings of links between language and action. Topics include neurocognitive studies of motor representations of speech sounds, action-related language, sign language and co-speech gestures. It will be concluded that there is strong evidence on the interaction between speech and gestures in the brain. This interaction however shares general properties with other domains in which there is interplay between language and action.

Abstract

Iconic words and signs are characterized by a perceived resemblance between aspects of their form and aspects of their meaning. For example, in English, iconic words include peep and crash, which mimic the sounds they denote, and wiggle and zigzag, which mimic motion. As a semiotic property of words and signs, iconicity has been demonstrated to play a role in word learning, language processing, and language evolution. This paper presents the results of a large-scale norming study for more than 14,000 English words conducted with over 1400 American English speakers. We demonstrate the utility of these ratings by replicating a number of existing findings showing that iconicity ratings are related to age of acquisition, sensory modality, semantic neighborhood density, structural markedness, and playfulness. We discuss possible use cases and limitations of the rating dataset, which is made publicly available.

Abstract

Vocal learning is a behavioral trait in which the social and acoustic environment shapes the vocal repertoire of individuals. Over the past century, the study of vocal learning has progressed at the intersection of ecology, physiology, neuroscience, molecular biology, genomics, and evolution. Yet, despite the complexity of this trait, vocal learning is frequently described as a binary trait, with species being classified as either vocal learners or vocal non-learners. As a result, studies have largely focused on a handful of species for which strong evidence for vocal learning exists. Recent studies, however, suggest a continuum in vocal learning capacity across taxa. Here, we further suggest that vocal learning is a multi-component behavioral phenotype comprised of distinct yet interconnected modules. Discretizing the vocal learning phenotype into its constituent modules would facilitate integration of findings across a wider diversity of species, taking advantage of the ways in which each excels in a particular module, or in a specific combination of features. Such comparative studies can improve understanding of the mechanisms and evolutionary origins of vocal learning. We propose an initial set of vocal learning modules supported by behavioral and neurobiological data and highlight the need for diversifying the field in order to disentangle the complexity of the vocal learning phenotype.

Abstract

Impaired emotion regulation may underlie exaggerated emotional reactivity in patients with obsessive compulsive disorder (OCD), yet instructed emotion regulation has never been studied in the disorder. METHOD: This study aimed to assess the neural correlates of emotion processing and regulation in 43 medication-free OCD patients and 38 matched healthy controls, and additionally test if these can be modulated by stimulatory (patients) and inhibitory (controls) repetitive transcranial magnetic stimulation (rTMS) over the left dorsolateral prefrontal cortex (dlPFC). Participants performed an emotion regulation task during functional magnetic resonance imaging before and after a single session of randomly assigned real or sham rTMS. Effect of group and rTMS were assessed on self-reported distress ratings and brain activity in frontal-limbic regions of interest. RESULTS: Patients had higher distress ratings than controls during emotion provocation, but similar rates of distress reduction after voluntary emotion regulation. OCD patients compared with controls showed altered amygdala responsiveness during symptom provocation and diminished left dlPFC activity and frontal-amygdala connectivity during emotion regulation. Real v. sham dlPFC stimulation differentially modulated frontal-amygdala connectivity during emotion regulation in OCD patients. CONCLUSIONS: We propose that the increased emotional reactivity in OCD may be due to a deficit in emotion regulation caused by a failure of cognitive control exerted by the dorsal frontal cortex. Modulatory rTMS over the left dlPFC may influence automatic emotion regulation capabilities by influencing frontal-limbic connectivity.

Abstract

In three cross-modal priming experiments we asked whether adaptation to a foreign-accented speaker is automatic, and whether adaptation can be seen after a long delay between initial exposure and test. Dutch listeners were exposed to a Hebrew-accented Dutch speaker with two types of Dutch words: those that contained [ɪ] (globally accented words), and those in which the Dutch [i] was shortened to [ɪ] (specific accent marker words). Experiment 1, which served as a baseline, showed that native Dutch participants showed facilitatory priming for globally accented, but not specific accent, words. In experiment 2, participants performed a 3.5-minute phoneme monitoring task, and were tested on their comprehension of the accented speaker 24 hours later using the same cross-modal priming task as in experiment 1. During the phoneme monitoring task, listeners were asked to detect a consonant that was not strongly accented. In experiment 3, the delay between exposure and test was extended to 1 week. Listeners in experiments 2 and 3 showed facilitatory priming for both globally accented and specific accent marker words. Together, these results show that adaptation to a foreign-accented speaker can be rapid and automatic, and can be observed after a prolonged delay in testing.

Abstract

To identify genetic variants associated with refractive astigmatism in the general population, meta-analyses of genome-wide association studies were performed for: White Europeans aged at least 25 years (20 cohorts, N = 31,968); Asian subjects aged at least 25 years (7 cohorts, N = 9,295); White Europeans aged <25 years (4 cohorts, N = 5,640); and all independent individuals from the above three samples combined with a sample of Chinese subjects aged <25 years (N = 45,931). Participants were classified as cases with refractive astigmatism if the average cylinder power in their two eyes was at least 1.00 diopter and as controls otherwise. Genome-wide association analysis was carried out for each cohort separately using logistic regression. Meta-analysis was conducted using a fixed effects model. In the older European group the most strongly associated marker was downstream of the neurexin-1 (NRXN1) gene (rs1401327, P = 3.92E−8). No other region reached genome-wide significance, and association signals were lower for the younger European group and Asian group. In the meta-analysis of all cohorts, no marker reached genome-wide significance: The most strongly associated regions were, NRXN1 (rs1401327, P = 2.93E−07), TOX (rs7823467, P = 3.47E−07) and LINC00340 (rs12212674, P = 1.49E−06). For 34 markers identified in prior GWAS for spherical equivalent refractive error, the beta coefficients for genotype versus spherical equivalent, and genotype versus refractive astigmatism, were highly correlated (r = −0.59, P = 2.10E−04). This work revealed no consistent or strong genetic signals for refractive astigmatism; however, the TOX gene region previously identified in GWAS for spherical equivalent refractive error was the second most strongly associated region. Analysis of additional markers provided evidence supporting widespread genetic co-susceptibility for spherical and astigmatic refractive errors.

Abstract

In het onderwijs wordt aangenomen dat hardop en stillezen dezelfde processen zijn. In dit onderzoek wordt gekeken naar het verschil tussen hardop en stillezen wat betreft leessnelheid en tekstbegrip bij 90 kinderen uit groep 4. Ook wordt de invloed van de cognitieve vaardigheden fonologisch bewustzijn, benoemsnelheid en visuele aandachtsspanne op de verschillende leesmodi onderzocht. De participanten lazen stil sneller, maar begrepen de tekst beter hardop. De cognitieve vaardigheden correleerden met hardop en stillezen wat betreft leessnelheid, maar hingen in beide leesmodi niet samen met tekstbegrip. Hoewel hardop en stillezen samenhangen, onderstrepen deze bevindingen dat het verschillende leesmodi zijn.

Abstract

This study aimed to increase our understanding on the relationship between reading and listening comprehension. Both in comprehension theory and in educational practice, reading and listening comprehension are often seen as interchangeable, overlooking modality-specific aspects of them separately. Three questions were addressed. First, it was examined to what extent reading and listening comprehension comprise modality-specific, distinct skills or an overlapping, domain-general skill in terms of the amount of explained variance in one comprehension type by the opposite comprehension type. Second, general and modality-unique subskills of reading and listening comprehension were sought by assessing the contributions of the foundational skills word reading fluency, vocabulary, memory, attention, and inhibition to both comprehension types. Lastly, the practice of using either listening comprehension or vocabulary as a proxy of general comprehension was investigated. Reading and listening comprehension tasks with the same format were assessed in 85 second and third grade children. Analyses revealed that reading comprehension explained 34% of the variance in listening comprehension, and listening comprehension 40% of reading comprehension. Vocabulary and word reading fluency were found to be shared contributors to both reading and listening comprehension. None of the other cognitive skills contributed significantly to reading or listening comprehension. These results indicate that only part of the comprehension process is indeed domain-general and not influenced by the modality in which the information is provided. Especially vocabulary seems to play a large role in this domain-general part. The findings warrant a more prominent focus of modality-specific aspects of both reading and listening comprehension in research and education.

Abstract

For bilinguals, speaking in a second language (L2) compared to the native language (L1) is usually more difficult. In this study we asked whether the difficulty in L2 production reflects increased demands imposed on domain-general or core language mechanisms. We compared the brain response to speech production in L1 and L2 within two functionally-defined networks in the brain: the Multiple Demand (MD) network and the language network. We found that speech production in L2 was linked to a widespread increase of brain activity in the domain-general MD network. The language network did not show a similarly robust differences in processing speech in the two languages, however, we found increased response to L2 production in the language-specific portion of the left inferior frontal gyrus (IFG). To further explore our results, we have looked at domain-general and language-specific response within the brain structures postulated to form a Bilingual Language Control (BLC) network. Within this network, we found a robust increase in response to L2 in the domain-general, but also in some language-specific voxels including in the left IFG. Our findings show that L2 production strongly engages domain-general mechanisms, but only affects language sensitive portions of the left IFG. These results put constraints on the current model of bilingual language control by precisely disentangling the domain-general and language-specific contributions to the difficulty in speech production in L2.

Abstract

When bilingual speakers switch back to speaking in their native language (L1) after having used their second language (L2), they often experience difficulty in retrieving words in their L1. This phenomenon is referred to as the L2 after-effect. We used the L2 after-effect as a lens to explore the neural bases of bilingual language control mechanisms. Our goal was twofold: first, to explore whether bilingual language control draws on domain-general or language-specific mechanisms; second, to investigate the precise mechanism(s) that drive the L2 after-effect. We used a precision fMRI approach based on functional localizers to measure the extent to which the brain activity that reflects the L2 after-effect overlaps with the language network (Fedorenko et al., 2010) and the domain-general multiple demand network (Duncan, 2010), as well as three task-specific networks that tap into interference resolution, lexical retrieval, and articulation. Forty-two Polish–English bilinguals participated in the study. Our results show that the L2 after-effect reflects increased engagement of domain-general but not language-specific resources. Furthermore, contrary to previously proposed interpretations, we did not find evidence that the effect reflects increased difficulty related to lexical access, articulation, and the resolution of lexical interference. We propose that difficulty of speech production in the picture naming paradigm—manifested as the L2 after-effect—reflects interference at a nonlinguistic level of task schemas or a general increase of cognitive control engagement during speech production in L1 after L2.

Abstract

Brain processing depends on the interactions between neuronal groups. Those interactions are governed by the pattern of anatomical connections and by yet unknown mechanisms that modulate the effective strength of a given connection. We found that the mutual influence among neuronal groups depends on the phase relation between rhythmic activities within the groups. Phase relations supporting interactions between the groups preceded those interactions by a few milliseconds, consistent with a mechanistic role. These effects were specific in time, frequency, and space, and we therefore propose that the pattern of synchronization flexibly determines the pattern of neuronal interactions.

Abstract

Diffusion tensor imaging (DTI) and a longitudinal language learning approach were applied to investigate the relationship between the achieved second language (L2) proficiency during L2 learning and the reorganization of structural connectivity between core language areas. Language proficiency tests and DTI scans were obtained from German students before and after they completed an intensive 6-week course of the Dutch language. In the initial learning stage, with increasing L2 proficiency, the hemispheric dominance of the BA6-temporal pathway (mainly along the arcuate fasciculus) shifted from the left to the right hemisphere. With further increased proficiency, however, lateralization dominance was again found in the left BA6-temporal pathway. This result is consistent with reports in the literature that imply a stronger involvement of the right hemisphere in L2-processing especially for less proficient L2-speakers. This is the first time that a L2-proficiency-dependent laterality shift in structural connectivity of language pathways during L2 acquisition has been observed to shift from left to right, and back to left hemisphere dominance with increasing L2-proficiency. We additionally find that changes in fractional anisotropy values after the course are related to the time elapsed between the two scans. The results suggest that structural connectivity in (at least part of) the perisylvian language network may be subject to fast dynamic changes following language learning

Abstract

There is substantial evidence that infants prefer infant-directed speech (IDS) to adult-directed speech (ADS). The strongest evidence for this claim has come from two large-scale investigations: i) a community-augmented meta-analysis of published behavioral studies and ii) a large-scale multi-lab replication study. In this paper, we aim to improve our understanding of the IDS preference and its boundary conditions by combining and comparing these two data sources across key population and design characteristics of the underlying studies. Our analyses reveal that both the meta-analysis and multi-lab replication show moderate effect sizes (d ≈ 0.35 for each estimate) and that both of these effects persist when relevant study-level moderators are added to the models (i.e., experimental methods, infant ages, and native languages). However, while the overall effect size estimates were similar, the two sources diverged in the effects of key moderators: both infant age and experimental method predicted IDS preference in the multi-lab replication study, but showed no effect in the meta-analysis. These results demonstrate that the IDS preference generalizes across a variety of experimental conditions and sampling characteristics, while simultaneously identifying key differences in the empirical picture offered by each source individually and pinpointing areas where substantial uncertainty remains about the influence of theoretically central moderators on IDS preference. Overall, our results show how meta-analyses and multi-lab replications can be used in tandem to understand the robustness and generalizability of developmental phenomena.

Abstract

Osteoblast induction and differentiation in developing long bones is dynamically controlled by the opposing action of transcriptional activators and repressors. In contrast to the long list of activators that have been discovered over past decades, the network of repressors is not well-defined. Here we identify the expression of Foxp1/2/4 proteins, comprised of Forkhead-box (Fox) transcription factors of the Foxp subfamily, in both perichondrial skeletal progenitors and proliferating chondrocytes during endochondral ossification. Mice carrying loss-of-function and gain-of-function Foxp mutations had gross defects in appendicular skeleton formation. At the cellular level, over-expression of Foxp1/2/4 in chondroctyes abrogated osteoblast formation and chondrocyte hypertrophy. Conversely, single or compound deficiency of Foxp1/2/4 in skeletal progenitors or chondrocytes resulted in premature osteoblast differentiation in the perichondrium, coupled with impaired proliferation, survival, and hypertrophy of chondrocytes in the growth plate. Foxp1/2/4 and Runx2 proteins interacted in vitro and in vivo, and Foxp1/2/4 repressed Runx2 transactivation function in heterologous cells. This study establishes Foxp1/2/4 proteins as coordinators of osteogenesis and chondrocyte hypertrophy in developing long bones and suggests that a novel transcriptional repressor network involving Foxp1/2/4 may regulate Runx2 during endochondral ossification.

Abstract

Face-selective regions (FSRs) are among the most widely studied functional regions in the human brain. However, individual variability of the FSRs has not been well quantified. Here we use functional magnetic resonance imaging (fMRI) to localize the FSRs and quantify their spatial and functional variabilities in 202 healthy adults. The occipital face area (OFA), posterior and anterior fusiform face areas (pFFA and aFFA), posterior continuation of the superior temporal sulcus (pcSTS), and posterior and anterior STS (pSTS and aSTS) were delineated for each individual with a semi-automated procedure. A probabilistic atlas was constructed to characterize their interindividual variability, revealing that the FSRs were highly variable in location and extent across subjects. The variability of FSRs was further quantified on both functional (i.e., face selectivity) and spatial (i.e., volume, location of peak activation, and anatomical location) features. Considerable interindividual variability and rightward asymmetry were found in all FSRs on these features. Taken together, our work presents the first effort to characterize comprehensively the variability of FSRs in a large sample of healthy subjects, and invites future work on the origin of the variability and its relation to individual differences in behavioral performance. Moreover, the probabilistic functional atlas will provide an adequate spatial reference for mapping the face network.

Abstract

In sentences like “the mouse that chased the cat was hungry”, the syntactically correct interpretation (the mouse chases the cat) is contradicted by semantic and pragmatic knowledge. Previous research has shown that L1 speakers sometimes base sentence interpretation on this type of knowledge (so-called “shallow” or “good-enough” processing). We made use of both behavioural and ERP measurements to investigate whether L2 learners differ from native speakers in the extent to which they engage in “shallow” syntactic processing. German learners of Dutch as well as Dutch native speakers read sentences containing relative clauses (as in the example above) for which the plausible thematic roles were or were not reversed, and made plausibility judgments. The results show that behaviourally, L2 learners had more difficulties than native speakers to discriminate plausible from implausible sentences. In the ERPs, we replicated the previously reported finding of a “semantic P600” for semantic reversal anomalies in native speakers, probably reflecting the effort to resolve the syntax-semantics conflict. In L2 learners, though, this P600 was largely attenuated and surfaced only in those trials that were judged correctly for plausibility. These results generally point at a more prevalent, but not exclusive occurrence of shallow syntactic processing in L2 learners.

Abstract

Statistical learning (SL) is postulated to play an important role in the process of language acquisition as well as in other cognitive functions. It was found to enable learning of various types of statistical patterns across different sensory modalities. However, few studies have distinguished distributional SL (DSL) from sequential and spatial SL, or examined DSL across modalities using comparable tasks. Considering the relevance of such findings to the nature of SL, the current study investigated the modality- and stimulus-specificity of DSL. Using a within-subject design we compared DSL performance in auditory and visual modalities. For each sensory modality, two stimulus types were used: linguistic versus non-linguistic auditory stimuli and temporal versus spatial visual stimuli. In each condition, participants were exposed to stimuli that varied in their length as they were drawn from two categories (short versus long). DSL was assessed using a categorization task and a production task. Results showed that learners’ performance was only correlated for tasks in the same sensory modality. Moreover, participants were better at categorizing the temporal signals in the auditory conditions than in the visual condition, where in turn an advantage of the spatial condition was observed. In the production task participants exaggerated signal length more for linguistic signals than non-linguistic signals. Together, these findings suggest that DSL is modality- and stimulus-sensitive.

Abstract

Semantic unification during sentence comprehension has been associated with amplitude change of the N400 in event-related potential (ERP) studies, and activation in the left inferior frontal gyrus (IFG) in functional magnetic resonance imaging (fMRI) studies. However, the specificity of this activation to semantic unification remains unknown. To more closely examine the brain processes involved in semantic unification, we employed simultaneous EEG-fMRI to time-lock the semantic unification related N400 change, and integrated trial-by-trial variation in both N400 and BOLD change beyond the condition-level BOLD change difference measured in traditional fMRI analyses. Participants read sentences in which semantic unification load was parametrically manipulated by varying cloze probability. Separately, ERP and fMRI results replicated previous findings, in that semantic unification load parametrically modulated the amplitude of N400 and cortical activation. Integrated EEG-fMRI analyses revealed a different pattern in which functional activity in the left IFG and bilateral supramarginal gyrus (SMG) was associated with N400 amplitude, with the left IFG activation and bilateral SMG activation being selective to the condition-level and trial-level of semantic unification load, respectively. By employing the EEG-fMRI integrated analyses, this study among the first sheds light on how to integrate trial-level variation in language comprehension.

Abstract

Genome-wide association studies using thousands to hundreds of thousands of single nucleotide polymorphism (SNP) markers and region-wide association studies using a dense panel of SNPs are already in use to identify disease susceptibility genes and to predict disease risk in individuals. Because these tasks become increasingly important, three different data sets were provided for the Genetic Analysis Workshop 15, thus allowing examination of various novel and existing data mining methods for both classification and identification of disease susceptibility genes, gene by gene or gene by environment interaction. The approach most often applied in this presentation group was random forests because of its simplicity, elegance, and robustness. It was used for prediction and for screening for interesting SNPs in a first step. The logistic tree with unbiased selection approach appeared to be an interesting alternative to efficiently select interesting SNPs. Machine learning, specifically ensemble methods, might be useful as pre-screening tools for large-scale association studies because they can be less prone to overfitting, can be less computer processor time intensive, can easily include pair-wise and higher-order interactions compared with standard statistical approaches and can also have a high capability for classification. However, improved implementations that are able to deal with hundreds of thousands of SNPs at a time are required.

Abstract

Research into the role of brain oscillations in basic perceptual and cognitive functions has suggested that the alpha rhythm reflects functional inhibition while the beta rhythm reflects neural ensemble (re)activation. However, little is known regarding the generalization of these proposed fundamental operations to linguistic processes, such as speech comprehension and production. Here, we recorded magnetoencephalography in participants performing a novel rule-switching paradigm. Specifically, Dutch native speakers had to produce an alternative exemplar from the same category or a feature of a given target word embedded in spoken sentences (e.g., for the word “tuna”, an exemplar from the same category—“seafood”—would be “shrimp”, and a feature would be “pink”). A cue indicated the task rule—exemplar or feature—either before (pre-cue) or after (retro-cue) listening to the sentence. Alpha power during the working memory delay was lower for retro-cue compared with that for pre-cue in the left hemispheric language-related regions. Critically, alpha power negatively correlated with reaction times, suggestive of alpha facilitating task performance by regulating inhibition in regions linked to lexical retrieval. Furthermore, we observed a different spatiotemporal pattern of beta activity for exemplars versus features in the right temporoparietal regions, in line with the proposed role of beta in recruiting neural networks for the encoding of distinct categories. Overall, our study provides evidence for the generalizability of the role of alpha and beta oscillations from perceptual to more “complex, linguistic processes” and offers a novel task to investigate links between rule-switching, working memory, and word production.

Abstract

Neural correlates of lexical stress were studied using the mismatch negativity (MMN) component in event-related potentials. The MMN responses were expected to reveal the encoding of stress information into long-term memory and the contributions of prosodic features such as fundamental frequency (F0) and intensity toward lexical access. In a passive oddball paradigm, neural responses to changes in F0, intensity, and in both features together were recorded for words and pseudowords. The findings showed significant differences not only between words and pseudowords but also between prosodic features. Early processing of prosodic information in words was indexed by an intensity-related MMN and an F0-related P200. These effects were stable at right-anterior and mid-anterior regions. At a later latency, MMN responses were recorded for both words and pseudowords at the mid-anterior and posterior regions. The P200 effect observed for F0 at the early latency for words developed into an MMN response. Intensity elicited smaller MMN for pseudowords than for words. Moreover, a larger brain area was recruited for the processing of words than for the processing of pseudowords. These findings suggest earlier and higher sensitivity to prosodic changes in words than in pseudowords, reflecting a language-related process. The present study, therefore, not only establishes neural correlates of lexical stress but also confirms the presence of long-term memory traces for prosodic information in the brain.

Abstract

Swedish morphemes are classified as prosodically specified or prosodically unspecified, depending on lexical or phonological stress, respectively. Here, we investigate the allomorphy of the suffix -(i)sk, which indicates the distinction between lexical and phonological stress; if attached to a lexically stressed morpheme, it takes a non-syllabic form (-sk), whereas if attached to a phonologically stressed morpheme, an epenthetic vowel is inserted (-isk). Using mismatch negativity (MMN), we explored the neural processing of this allomorphy across lexically stressed and phonologically stressed morphemes. In an oddball paradigm, participants were occasionally presented with congruent and incongruent derivations, created by the suffix -(i)sk, within the repetitive presentation of their monomorphemic stems. The results indicated that the congruent derivation of the lexically stressed stem elicited a larger MMN than the incongruent sequences of the same stem and the derivational suffix, whereas after the phonologically stressed stem a non-significant tendency towards an opposite pattern was observed. We argue that the significant MMN response to the congruent derivation in the lexical stress condition is in line with lexical MMN, indicating a holistic processing of the sequence of lexically stressed stem and derivational suffix. The enhanced MMN response to the incongruent derivation in the phonological stress condition, on the other hand, is suggested to reflect combinatorial processing of the sequence of phonologically stressed stem and derivational suffix. These findings bring a new aspect to the dual-system approach to neural processing of morphologically complex words, namely the specification of word stress.

Abstract

Speakers remember their own utterances better than those of their interlocutors, suggesting that language production is beneficial to memory. This may be partly explained by a generation effect: The act of generating a word is known to lead to a memory advantage (Slamecka & Graf, 1978). In earlier work, we showed a generation effect for recognition of images (Zormpa, Brehm, Hoedemaker, & Meyer, 2019). Here, we tested whether the recognition of their names would also benefit from name generation. Testing whether picture naming improves memory for words was our primary aim, as it serves to clarify whether the representations affected by generation are visual or conceptual/lexical. A secondary aim was to assess the influence of processing time on memory. Fifty-one participants named pictures in three conditions: after hearing the picture name (identity condition), backward speech, or an unrelated word. A day later, recognition memory was tested in a yes/no task. Memory in the backward speech and unrelated conditions, which required generation, was superior to memory in the identity condition, which did not require generation. The time taken by participants for naming was a good predictor of memory, such that words that took longer to be retrieved were remembered better. Importantly, that was the case only when generation was required: In the no-generation (identity) condition, processing time was not related to recognition memory performance. This work has shown that generation affects conceptual/lexical representations, making an important contribution to the understanding of the relationship between memory and language.

Abstract

The production effect (better memory for words read aloud than words read silently) and the picture superiority effect (better memory for pictures than words) both improve item memory in a picture naming task (Fawcett, J. M., Quinlan, C. K., & Taylor, T. L. (2012). Interplay of the production and picture superiority effects: A signal detection analysis. Memory (Hove, England), 20(7), 655–666. doi:10.1080/09658211.2012.693510). Because picture naming requires coming up with an appropriate label, the generation effect (better memory for generated than read words) may contribute to the latter effect. In two forced-choice memory experiments, we tested the role of generation in a picture naming task on later recognition memory. In Experiment 1, participants named pictures silently or aloud with the correct name or an unreadable label superimposed. We observed a generation effect, a production effect, and an interaction between the two. In Experiment 2, unreliable labels were included to ensure full picture processing in all conditions. In this experiment, we observed a production and a generation effect but no interaction, implying the effects are dissociable. This research demonstrates the separable roles of generation and production in picture naming and their impact on memory. As such, it informs the link between memory and language production and has implications for memory asymmetries between language production and comprehension.