Diverging neural dynamics for syntactic structure building in naturalistic speaking and listening.

The neural correlates of sentence production are typically studied using task paradigms that differ considerably from the experience of speaking outside of an experimental setting. In this fMRI study, we aimed to gain a better understanding of syntactic processing in spontaneous production versus naturalistic comprehension in three regions of interest (BA44, BA45, and left posterior middle temporal gyrus). A group of participants (n = 16) was asked to speak about the events of an episode of a TV series in the scanner. Another group of participants (n = 36) listened to the spoken recall of a participant from the first group. To model syntactic processing, we extracted word-by-word metrics of phrase-structure building with a top-down and a bottom-up parser that make different hypotheses about the timing of structure building. While the top-down parser anticipates syntactic structure, sometimes before it is obvious to the listener, the bottom-up parser builds syntactic structure in an integratory way after all of the evidence has been presented. In comprehension, neural activity was found to be better modeled by the bottom-up parser, while in production, it was better modeled by the top-down parser. We additionally modeled structure building in production with two strategies that were developed here to make different predictions about the incrementality of structure building during speaking. We found evidence for highly incremental and anticipatory structure building in production, which was confirmed by a converging analysis of the pausing patterns in speech. Overall, this study shows the feasibility of studying the neural dynamics of spontaneous language production.

Commonalities and Asymmetries in the Neurobiological Infrastructure for Language Production and Comprehension.

The neurobiology of sentence production has been largely understudied compared to the neurobiology of sentence comprehension, due to difficulties with experimental control and motion-related artifacts in neuroimaging. We studied the neural response to constituents of increasing size and specifically focused on the similarities and differences in the production and comprehension of the same stimuli. Participants had to either produce or listen to stimuli in a gradient of constituent size based on a visual prompt. Larger constituent sizes engaged the left inferior frontal gyrus (LIFG) and middle temporal gyrus (LMTG) extending to inferior parietal areas in both production and comprehension, confirming that the neural resources for syntactic encoding and decoding are largely overlapping. An ROI analysis in LIFG and LMTG also showed that production elicited larger responses to constituent size than comprehension and that the LMTG was more engaged in comprehension than production, while the LIFG was more engaged in production than comprehension. Finally, increasing constituent size was characterized by later BOLD peaks in comprehension but earlier peaks in production. These results show that syntactic encoding and parsing engage overlapping areas, but there are asymmetries in the engagement of the language network due to the specific requirements of production and comprehension.

Does Neuronal Recycling Result in Destructive Competition? The Influence of Learning to Read on the Recognition of Faces.

Written language, a human cultural invention, is far too recent a development for dedicated neural infrastructure to have evolved in its service. Newly acquired cultural skills, such as reading, thus recycle evolutionarily older circuits that originally evolved for different, but similar, functions (e.g., visual object recognition). The destructive-competition hypothesis predicts that this neuronal recycling has detrimental behavioral effects on the cognitive functions for which a cortical network originally evolved. In a study with 97 literate, low-literate, and illiterate participants from the same socioeconomic background, we found that even after adjusting for cognitive ability and test-taking familiarity, learning to read was associated with an increase, rather than a decrease, in object-recognition abilities. These results are incompatible with the claim that neuronal recycling results in destructive competition and are consistent with the possibility that learning to read instead fine-tunes general object-recognition mechanisms, a hypothesis that needs further neuroscientific investigation.

Practices and pitfalls in inferring neural representations.

A key challenge for cognitive neuroscience is deciphering the representational schemes of the brain. Stimulus-feature-based encoding models are becoming increasingly popular for inferring the dimensions of neural representational spaces from stimulus-feature spaces. We argue that such inferences are not always valid because successful prediction can occur even if the two representational spaces use different, but correlated, representational schemes. We support this claim with three simulations in which we achieved high prediction accuracy despite systematic differences in the geometries and dimensions of the underlying representations. Detailed analysis of the encoding models' predictions showed systematic deviations from ground-truth, indicating that high prediction accuracy is insufficient for making representational inferences. This fallacy applies to the prediction of actual neural patterns from stimulus-feature spaces and we urge caution in inferring the nature of the neural code from such methods. We discuss ways to overcome these inferential limitations, including model comparison, absolute model performance, visualization techniques and attentional modulation.

Introducing a replication-first rule for Ph.D. projects.

Zwaan et al. mention that young researchers should conduct replications as a small part of their portfolio. We extend this proposal and suggest that conducting and reporting replications should become an integral part of Ph.D. projects and be taken into account in their assessment. We discuss how this would help not only scientific advancement, but also Ph.D. candidates' careers.

Feel the Noise: Relating Individual Differences in Auditory Imagery to the Structure and Function of Sensorimotor Systems.

Humans can generate mental auditory images of voices or songs, sometimes perceiving them almost as vividly as perceptual experiences. The functional networks supporting auditory imagery have been described, but less is known about the systems associated with interindividual differences in auditory imagery. Combining voxel-based morphometry and fMRI, we examined the structural basis of interindividual differences in how auditory images are subjectively perceived, and explored associations between auditory imagery, sensory-based processing, and visual imagery. Vividness of auditory imagery correlated with gray matter volume in the supplementary motor area (SMA), parietal cortex, medial superior frontal gyrus, and middle frontal gyrus. An analysis of functional responses to different types of human vocalizations revealed that the SMA and parietal sites that predict imagery are also modulated by sound type. Using representational similarity analysis, we found that higher representational specificity of heard sounds in SMA predicts vividness of imagery, indicating a mechanistic link between sensory- and imagery-based processing in sensorimotor cortex. Vividness of imagery in the visual domain also correlated with SMA structure, and with auditory imagery scores. Altogether, these findings provide evidence for a signature of imagery in brain structure, and highlight a common role of perceptual-motor interactions for processing heard and internally generated auditory information.

Testing the involvement of low-level visual representations during spoken word processing with non-Western students and meditators practicing Sudarshan Kriya Yoga.

Previous studies, using the Continuous Flash Suppression (CFS) paradigm, observed that (Western) university students are better able to detect otherwise invisible pictures of objects when they are presented with the corresponding spoken word shortly before the picture appears. Here we attempted to replicate this effect with non-Western university students in Goa (India). A second aim was to explore the performance of (non-Western) meditators practicing Sudarshan Kriya Yoga in Goa in the same task. Some previous literature suggests that meditators may excel in some tasks that tap visual attention, for example by exercising better endogenous and exogenous control of visual awareness than non-meditators. The present study replicated the finding that congruent spoken cue words lead to significantly higher detection sensitivity than incongruent cue words in non-Western university students. Our exploratory meditator group also showed this detection effect but both frequentist and Bayesian analyses suggest that the practice of meditation did not modulate it. Overall, our results provide further support for the notion that spoken words can activate low-level category-specific visual features that boost the basic capacity to detect the presence of a visual stimulus that has those features. Further research is required to conclusively test whether meditation can modulate visual detection abilities in CFS and similar tasks.

No evidence for embodiment: The motor system is not needed to keep action verbs in working memory.

Increasing evidence implicates the sensorimotor systems with high-level cognition, but the extent to which these systems play a functional role remains debated. Using an elegant design, Shebani and Pulvermüller (2013) reported that carrying out a demanding rhythmic task with the hands led to selective impairment of working memory for hand-related words (e.g., clap), while carrying out the same task with the feet led to selective memory impairment for foot-related words (e.g., kick). Such a striking double dissociation is acknowledged even by critics to constitute strong evidence for an embodied account of working memory. Here, we report on an attempt at a direct replication of this important finding. We followed a sequential sampling design and stopped data collection at N = 77 (more than five times the original sample size), at which point the evidence for the lack of the critical selective interference effect was very strong (BF01 = 91). This finding constitutes strong evidence against a functional contribution of the motor system to keeping action verbs in working memory. Our finding fits into the larger emerging picture in the field of embodied cognition that sensorimotor simulations are neither required nor automatic in high-level cognitive processes, but that they may play a role depending on the task. Importantly, we invite researchers to engage in transparent, high-powered, and fully pre-registered experiments like the present one to ensure the field advances on a solid basis.

A pre-registered, multi-lab non-replication of the action-sentence compatibility effect (ACE).

The Action-sentence Compatibility Effect (ACE) is a well-known demonstration of the role of motor activity in the comprehension of language. Participants are asked to make sensibility judgments on sentences by producing movements toward the body or away from the body. The ACE is the finding that movements are faster when the direction of the movement (e.g., toward) matches the direction of the action in the to-be-judged sentence (e.g., Art gave you the pen describes action toward you). We report on a pre-registered, multi-lab replication of one version of the ACE. The results show that none of the 18 labs involved in the study observed a reliable ACE, and that the meta-analytic estimate of the size of the ACE was essentially zero.

Towards Strong Inference in Research on Embodiment - Possibilities and Limitations of Causal Paradigms.

A central question in the cognitive sciences is which role embodiment plays for high-level cognitive functions, such as conceptual processing. Here, we propose that one reason why progress regarding this question has been slow is a lacking focus on what Platt (1964) called "strong inference". Strong inference is possible when results from an experimental paradigm are not merely consistent with a hypothesis, but they provide decisive evidence for one particular hypothesis compared to competing hypotheses. We discuss how causal paradigms, which test the functional relevance of sensory-motor processes for high-level cognitive functions, can move the field forward. In particular, we explore how congenital sensory-motor disorders, acquired sensory-motor deficits, and interference paradigms with healthy participants can be utilized as an opportunity to better understand the role of sensory experience in conceptual processing. Whereas all three approaches can bring about valuable insights, we highlight that the study of congenitally and acquired sensorimotor disorders is particularly effective in the case of conceptual domains with strong unimodal basis (e.g., colors), whereas interference paradigms with healthy participants have a broader application, avoid many of the practical and interpretational limitations of patient studies, and allow a systematic and step-wise progressive inference approach to causal mechanisms.

Evidence for visual simulation during sign language processing.

What are the mental processes that allow us to understand the meaning of words? A large body of evidence suggests that when we process speech, we engage a process of perceptual simulation whereby sensorimotor states are activated as a source of semantic information. But does the same process take place when words are expressed with the hands and perceived through the eyes? To date, it is not known whether perceptual simulation is also observed in sign languages, the manual-visual languages of deaf communities. Continuous flash suppression is a method that addresses this question by measuring the effect of language on detection sensitivity to images that are suppressed from awareness. In spoken languages, it has been reported that listening to a word (e.g., "bottle") activates visual features of an object (e.g., the shape of a bottle), and this in turn facilitates image detection. An interesting but untested question is whether the same process takes place when deaf signers see signs. We found that processing signs boosted the detection of congruent images, making otherwise invisible pictures visible. A boost of visual processing was observed only for signers but not for hearing nonsigners, suggesting that the penetration of the visual system through signs requires a fully fledged manual language. Iconicity did not modulate the effect of signs on detection, neither in signers nor in hearing nonsigners. This suggests that visual simulation during language processing occurs regardless of language modality (sign vs. speech) or iconicity, pointing to a foundational role of simulation for language comprehension. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Does using a foreign language reduce mental imagery?

In a recent article, Hayakawa and Keysar (2018) propose that mental imagery is less vivid when evoked in a foreign than in a native language. The authors argue that reduced mental imagery could even account for moral foreign language effects, whereby moral choices become more utilitarian when made in a foreign language. Here we demonstrate that Hayakawa and Keysar's (2018) key results are better explained by reduced language comprehension in a foreign language than by less vivid imagery. We argue that the paradigm used in Hayakawa and Keysar (2018) does not provide a satisfactory test of reduced imagery and we discuss an alternative paradigm based on recent experimental developments.

Distinguishing integration and prediction accounts of ERP N400 modulations in language processing through experimental design.

Many theoretical accounts of prediction in language processing are based to a substantial amount on experimental evidence from electrophysiological studies measuring N400 target word modulations. A drawback of most of these studies is that lexical prediction ('top-down' activation) accounts cannot be distinguished conclusively from lexical integration ('bottom-up' activation) accounts. Here we explored whether it is possible to distinguish integration and prediction accounts of ERP N400 modulations in language processing through experimental design. By employing rhyming sentence completions, we kept the ease of integration constant across conditions that differed in word predictability only. This experimental design allowed us to attribute N400 target word effects across conditions to predictive language processing. We close by discussing recommendations for future electrophysiological studies on prediction in language.

Are visual processes causally involved in "perceptual simulation" effects in the sentence-picture verification task?

Many studies have shown that sentences implying an object to have a certain shape produce a robust reaction time advantage for shape-matching pictures in the sentence-picture verification task. Typically, this finding has been interpreted as evidence for perceptual simulation, i.e., that access to implicit shape information involves the activation of modality-specific visual processes. It follows from this proposal that disrupting visual processing during sentence comprehension should interfere with perceptual simulation and obliterate the match effect. Here we directly test this hypothesis. Participants listened to sentences while seeing either visual noise that was previously shown to strongly interfere with basic visual processing or a blank screen. Experiments 1 and 2 replicated the match effect but crucially visual noise did not modulate it. When an interference technique was used that targeted high-level semantic processing (Experiment 3) however the match effect vanished. Visual noise specifically targeting high-level visual processes (Experiment 4) only had a minimal effect on the match effect. We conclude that the shape match effect in the sentence-picture verification paradigm is unlikely to rely on perceptual simulation.

Saccade trajectories reveal dynamic interactions of semantic and spatial information during the processing of implicitly spatial words.

Implicit up/down words, such as bird and foot, systematically influence performance on visual tasks involving immediately following targets in compatible versus incompatible locations. Recent studies have observed that the semantic relation between prime words and target pictures can strongly influence the size and even the direction of the effect: Semantically related targets are processed faster in congruent versus incongruent locations (location-specific priming), whereas unrelated targets are processed slower in congruent locations. Here, we used eye-tracking to investigate the moment-to-moment processes underlying this pattern. Our reaction time (RT) results for related targets replicated the location-specific priming effect and showed a trend toward interference for unrelated targets. We then used growth curve analysis to test how up/down words and their match versus mismatch with immediately following targets in terms of semantics and vertical location influence concurrent saccadic eye movements. There was a strong main effect of spatial association on linear growth, with up words biasing changes in y-coordinates over time upward relative to down words (and vice versa). Similar to the case with the RT data, this effect was strongest for semantically related targets and reversed for unrelated targets. It is intriguing that all conditions showed a bias in the congruent direction in the initial stage of the saccade. Then, at around halfway into the saccade the effect kept increasing in the semantically related condition and reversed in the unrelated condition. These results suggest that online processing of up/down words triggers direction-specific oculomotor processes that are dynamically modulated by the semantic relation between prime words and targets. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Spoken words can make the invisible visible-Testing the involvement of low-level visual representations in spoken word processing.

The notion that processing spoken (object) words involves activation of category-specific representations in visual cortex is a key prediction of modality-specific theories of representation that contrasts with theories assuming dedicated conceptual representational systems abstracted away from sensorimotor systems. In the present study, we investigated whether participants can detect otherwise invisible pictures of objects when they are presented with the corresponding spoken word shortly before the picture appears. Our results showed facilitated detection for congruent ("bottle" → picture of a bottle) versus incongruent ("bottle" → picture of a banana) trials. A second experiment investigated the time-course of the effect by manipulating the timing of picture presentation relative to word onset and revealed that it arises as soon as 200-400 ms after word onset and decays at 600 ms after word onset. Together, these data strongly suggest that spoken words can rapidly activate low-level category-specific visual representations that affect the mere detection of a stimulus, that is, what we see. More generally, our findings fit best with the notion that spoken words activate modality-specific visual representations that are low level enough to provide information related to a given token and at the same time abstract enough to be relevant not only for previously seen tokens but also for generalizing to novel exemplars one has never seen before. (PsycINFO Database Record

A task-dependent causal role for low-level visual processes in spoken word comprehension.

It is well established that the comprehension of spoken words referring to object concepts relies on high-level visual areas in the ventral stream that build increasingly abstract representations. It is much less clear whether basic low-level visual representations are also involved. Here we asked in what task situations low-level visual representations contribute functionally to concrete word comprehension using an interference paradigm. We interfered with basic visual processing while participants performed a concreteness task (Experiment 1), a lexical-decision task (Experiment 2), and a word class judgment task (Experiment 3). We found that visual noise interfered more with concrete versus abstract word processing, but only when the task required visual information to be accessed. This suggests that basic visual processes can be causally involved in language comprehension, but that their recruitment is not automatic and rather depends on the type of information that is required in a given task situation. (PsycINFO Database Record

Reading sky and seeing a cloud: On the relevance of events for perceptual simulation.

Previous research has shown that processing words with an up/down association (e.g., bird, foot) can influence the subsequent identification of visual targets in congruent location (at the top/bottom of the screen). However, as facilitation and interference were found under similar conditions, the nature of the underlying mechanisms remained unclear. We propose that word comprehension relies on the perceptual simulation of a prototypical event involving the entity denoted by a word in order to provide a general account of the different findings. In 3 experiments, participants had to discriminate between 2 target pictures appearing at the top or the bottom of the screen by pressing the left versus right button. Immediately before the targets appeared, they saw an up/down word belonging to the target's event, an up/down word unrelated to the target, or a spatially neutral control word. Prime words belonging to target event facilitated identification of targets at a stimulus onset asynchrony (SOA) of 250 ms (Experiment 1), but only when presented in the vertical location where they are typically seen, indicating that targets were integrated in the simulations activated by the prime words. Moreover, at the same SOA, there was a robust facilitation effect for targets appearing in their typical location regardless of the prime type. However, when words were presented for 100 ms (Experiment 2) or 800 ms (Experiment 3), only a location nonspecific priming effect was found, suggesting that the visual system was not activated. Implications for theories of semantic processing are discussed. (PsycINFO Database Record