Publications

Abstract

Speakers adjust their voice when talking in noise, which is known as Lombard speech. These acoustic adjustments facilitate speech comprehension in noise relative to plain speech (i.e., speech produced in quiet). However, exactly which characteristics of Lombard speech drive this intelligibility benefit in noise remains unclear. This study assessed the contribution of enhanced amplitude modulations to the Lombard speech intelligibility benefit by demonstrating that (1) native speakers of Dutch in the Nijmegen Corpus of Lombard Speech (NiCLS) produce more pronounced amplitude modulations in noise vs. in quiet; (2) more enhanced amplitude modulations correlate positively with intelligibility in a speech-in-noise perception experiment; (3) transplanting the amplitude modulations from Lombard speech onto plain speech leads to an intelligibility improvement, suggesting that enhanced amplitude modulations in Lombard speech contribute towards intelligibility in noise. Results are discussed in light of recent neurobiological models of speech perception with reference to neural oscillators phase-locking to the amplitude modulations in speech, guiding the processing of speech.

Abstract

Spoken words are highly variable and therefore listeners interpret speech sounds relative to the surrounding acoustic context, such as the speech rate of a preceding sentence. For instance, a vowel midway between short /ɑ/ and long /a:/ in Dutch is perceived as short /ɑ/ in the context of preceding slow speech, but as long /a:/ if preceded by a fast context. Despite the well-established influence of visual articulatory cues on speech comprehension, it remains unclear whether visual cues to speech rate also influence subsequent spoken word recognition. In two ‘Go Fish’-like experiments, participants were presented with audio-only (auditory speech + fixation cross), visual-only (mute videos of talking head), and audiovisual (speech + videos) context sentences, followed by ambiguous target words containing vowels midway between short /ɑ/ and long /a:/. In Experiment 1, target words were always presented auditorily, without visual articulatory cues. Although the audio-only and audiovisual contexts induced a rate effect (i.e., more long /a:/ responses after fast contexts), the visual-only condition did not. When, in Experiment 2, target words were presented audiovisually, rate effects were observed in all three conditions, including visual-only. This suggests that visual cues to speech rate in a context sentence influence the perception of following visual target cues (e.g., duration of lip aperture), which at an audiovisual integration stage bias participants’ target categorization responses. These findings contribute to a better understanding of how what we see influences what we hear.

Abstract

Two fundamental properties of perception are selective attention and perceptual contrast, but how these two processes interact remains unknown. Does an attended stimulus history exert a larger contrastive influence on the perception of a following target than unattended stimuli? Dutch listeners categorized target sounds with a reduced prefix “ge-” marking tense (e.g., ambiguous between gegaan-gaan “gone-go”). In ‘single talker’ Experiments 1–2, participants perceived the reduced syllable (reporting gegaan) when the target was heard after a fast sentence, but not after a slow sentence (reporting gaan). In ‘selective attention’ Experiments 3–5, participants listened to two simultaneous sentences from two different talkers, followed by the same target sounds, with instructions to attend only one of the two talkers. Critically, the speech rates of attended and unattended talkers were found to equally influence target perception – even when participants could watch the attended talker speak. In fact, participants’ target perception in ‘selective attention’ Experiments 3–5 did not differ from participants who were explicitly instructed to divide their attention equally across the two talkers (Experiment 6). This suggests that contrast effects of speech rate are immune to selective attention, largely operating prior to attentional stream segregation in the auditory processing hierarchy.

Abstract

Speech sounds are perceived relative to spectral properties of surrounding speech. For instance, target words ambiguous between /bɪt/ (with low F1) and /bɛt/ (with high F1) are more likely to be perceived as “bet” after a ‘low F1’ sentence, but as “bit” after a ‘high F1’ sentence. However, it is unclear how these spectral contrast effects (SCEs) operate in multi-talker listening conditions. Recently, Feng and Oxenham [(2018b). J.Exp.Psychol.-Hum.Percept.Perform. 44(9), 1447–1457] reported that selective attention affected SCEs to a small degree, using two simultaneously presented sentences produced by a single talker. The present study assessed the role of selective attention in more naturalistic ‘cocktail party’ settings, with 200 lexically unique sentences, 20 target words, and different talkers. Results indicate that selective attention to one talker in one ear (while ignoring another talker in the other ear) modulates SCEs in such a way that only the spectral properties of the attended talker influences target perception. However, SCEs were much smaller in multi-talker settings (Experiment 2) than those in single-talker settings (Experiment 1). Therefore, the influence of SCEs on speech comprehension in more naturalistic settings (i.e., with competing talkers) may be smaller than estimated based on studies without competing talkers.

Abstract

Agreement attraction in comprehension (when an ungrammatical verb is read quickly if preceded by a feature-matching local noun) is well described by a cue-based retrieval framework. This suggests a role for lexical retrieval in attraction. To examine this, we manipulated two probabilistic factors known to affect lexical retrieval: local noun word frequency and morpho-orthography (agreement morphology realised with or without –s endings) in a self-paced reading study. Noun number and word frequency affected noun and verb region reading times, with higher-frequency words not eliciting attraction. Morpho-orthography impacted verb processing but not attraction: atypical plurals led to slower verb reading times regardless of verb number. Exploratory individual difference analyses further underscore the importance of lexical retrieval dynamics in sentence processing. This provides evidence that agreement operates via a cue-based retrieval mechanism over lexical representations that vary in their strength and association to number features.

Abstract

Book reading shows large individual variability and correlates with better language ability and more empathy. This makes reading exposure an interesting variable to study. Research in English suggests that an author recognition test is the most reliable objective assessment of reading frequency. In this article, we describe the efforts we made to build and test a Dutch author recognition test (DART for older participants and DART_R for younger participants). Our data show that the test is reliable and valid, both in the Netherlands and in Belgium (split-half reliability over .9 with university students, significant correlations with language abilities) and can be used with a young, non-university population. The test is free to use for research purposes.

Abstract

Previous work found that single-session focused attention meditation (FAM) enhanced motor sequence learning through increased cognitive control as a mechanistic action, although electrophysiological correlates of sequence learning performance following FAM were not investigated. We measured the persistent frontal N2 event-related potential (ERP) that is closely related to cognitive control processes and its ability to predict behavioural measures. Twenty-nine participants were randomised to one of three conditions reflecting the level of FAM experienced prior to a serial reaction time task (SRTT): 21 sessions of FAM (FAM21, N = 12), a single FAM session (FAM1, N = 9) or no preceding FAM control (Control, N = 8). Continuous 64-channel EEG were recorded during SRTT and N2 amplitudes for correct trials were extracted. Component amplitude, regions of interests, and behavioural outcomes were compared using mixed effects regression models between groups. FAM21 exhibited faster reaction time performances in majority of the learning blocks compared to FAM1 and Control. FAM21 also demonstrated a significantly more pronounced N2 over majority of anterior and central regions of interests during SRTT compared to the other groups. When N2 amplitudes were modelled against general learning performance, FAM21 showed the greatest rate of amplitude decline over anterior and central regions. The combined results suggest that FAM training provided greater cognitive control enhancement for improved general performance, and less pronounced effects for sequence-specific learning performance compared to the other groups. Importantly, FAM training facilitates dynamic modulation of cognitive control: lower levels of general learning performance was supported by greater levels of activation, whilst higher levels of general learning exhibited less activation.

Abstract

Alpha-band oscillatory activity is involved in modulating memory and attention. However, few studies have investigated individual differences in oscillatory activity during the encoding of emotional memory, particularly in sleep paradigms where sleep is thought to play an active role in memory consolidation. The current study aimed to address the question of whether individual alpha frequency (IAF) modulates the consolidation of declarative memory across periods of sleep and wake. 22 participants aged 18 – 41 years (mean age = 25.77) viewed 120 emotionally valenced images (positive, negative, neutral) and completed a baseline memory task before a 2hr afternoon sleep opportunity and an equivalent period of wake. Following the sleep and wake conditions, participants were required to distinguish between 120 learned (target) images and 120 new (distractor) images. This method allowed us to delineate the role of different oscillatory components of sleep and wake states in the emotional modulation of memory. Linear mixed-effects models revealed interactions between IAF, rapid eye movement sleep theta power, and slow-wave sleep slow oscillatory density on memory outcomes. These results highlight the importance of individual factors in the EEG in modulating oscillatory-related memory consolidation and subsequent behavioural outcomes and test predictions proposed by models of sleep-based memory consolidation.

Abstract

There is an ongoing debate about whether discourse biases can constrain sentence
processing. Previous work has shown comprehension question accuracy to decrease
for temporarily ambiguous sentences preceded by a context biasing towards an initial
misinterpretation, suggesting a role of context for modulating comprehension.
However, this creates limited modulation of reading times at the disambiguating word,
suggesting initial syntactic processing may be unaffected by context [Christianson &
Luke, 2011. Context strengthens initial misinterpretations of text. Scientific Studies of
Reading, 15(2), 136–166]. The current experiments examine whether propositional and
structural content from preceding comprehension questions can cue readers to expect
certain structures in temporarily ambiguous garden-path sentences. The central finding
is that syntactic repair processes remain unaffected while reading times in other
regions are modulated by preceding questions. This suggests that reading strategies
can be superficially influenced by preceding comprehension questions without
impacting the fidelity of ultimate (mis)representations.

Abstract

The present article examines the proposal that typology is a major factor guiding transfer selectivity in L3/Ln acquisition. We tested first exposure in L3/Ln using two artificial languages (ALs) lexically based in English and Spanish, focusing on gender agreement between determiners and nouns, and between nouns and adjectives. 50 L1 Spanish-L2 English speakers took part in the experiment. After receiving implicit training in one of the ALs (Mini-Spanish, N = 26; Mini-English, N = 24), gender violations elicited a fronto-lateral negativity in Mini-English in the earliest time window (200–500 ms), although this was not followed by any other differences in subsequent periods. This effect was highly localized, surfacing only in electrodes of the right-anterior region. In contrast, gender violations in Mini-Spanish elicited a broadly distributed positivity in the 300–600 ms time window. While we do not find typical indices of grammatical processing such as the P600 component, we believe that the between-groups differential appearance of the positivity for gender violations in the 300–600 ms time window reflects differential allocation of attentional resources as a function of the ALs’ lexical similarity to English or Spanish. We take these differences in attention to be precursors of the processes involved in transfer source selection in L3/Ln.

Abstract

The representations generated by many mod-
els of language (word embeddings, recurrent
neural networks and transformers) correlate
to brain activity recorded while people read.
However, these decoding results are usually
based on the brain’s reaction to syntactically
and semantically sound language stimuli. In
this study, we asked: how does an LSTM (long
short term memory) language model, trained
(by and large) on semantically and syntac-
tically intact language, represent a language
sample with degraded semantic or syntactic
information? Does the LSTM representation
still resemble the brain’s reaction? We found
that, even for some kinds of nonsensical lan-
guage, there is a statistically significant rela-
tionship between the brain’s activity and the
representations of an LSTM. This indicates
that, at least in some instances, LSTMs and the
human brain handle nonsensical data similarly.

Abstract

Contemporary accounts of anticipatory language processing assume that individuals predict upcoming information at multiple levels of representation. Research investigating language-mediated anticipatory eye gaze typically assumes that linguistic input restricts the domain of subsequent reference (visual target objects). Here, we explored the converse case: Can visual input restrict the dynamics of anticipatory language processing? To this end, we recorded participants’ eye movements as they listened to sentences in which an object was predictable based on the verb’s selectional restrictions (“The man peels a banana”). While listening, participants looked at different types of displays: The target object (banana) was either present or it was absent. On target-absent trials, the displays featured objects that had a similar visual shape as the target object (canoe) or objects that were semantically related to the concepts invoked by the target (monkey). Each trial was presented in a long preview version, where participants saw the displays for approximately 1.78 seconds before the verb was heard (pre-verb condition), and a short preview version, where participants saw the display approximately 1 second after the verb had been heard (post-verb condition), 750 ms prior to the spoken target onset. Participants anticipated the target objects in both conditions. Importantly, robust evidence for predictive looks to objects related to the (absent) target objects in visual shape and semantics was found in the post-verb but not in the pre-verb condition. These results suggest that visual information can restrict language-mediated anticipatory gaze and delineate theoretical accounts of predictive processing in the visual world.

Abstract

Previous studies have shown that during comprehension readers activate words beyond the unfolding sentence. An open question concerns the mechanisms underlying this behavior. One proposal is that readers mentally simulate the described event and activate related words that might be referred to as the discourse further unfolds. Another proposal is that activation between words spreads in an automatic, associative fashion. The empirical support for these proposals is mixed. Therefore, theoretical accounts differ with regard to how much weight they place on the contributions of these sources to sentence comprehension. In the present study, we attempted to assess the contributions of event simulation and lexical associations to discourse reading, using event-related brain potentials (ERPs). Participants read target words, which were preceded by associatively related words either appearing in a coherent discourse event (Experiment 1) or in sentences that did not form a coherent discourse event (Experiment 2). Contextually unexpected target words that were associatively related to the described events elicited a reduced N400 amplitude compared to contextually unexpected target words that were unrelated to the events (Experiment 1). In Experiment 2, a similar but reduced effect was observed. These findings support the notion that during discourse reading event simulation and simple word associations jointly contribute to language comprehension by activating words that are beyond contextually congruent sentence continuations.

Abstract

- * indicates joint first authorship - Lexical access is a core component of word processing. In order to produce or comprehend a word, language users must access word forms in their mental lexicon. However, despite its involvement in both tasks, previous research has often studied lexical access in either production or comprehension alone. Therefore, it is unknown to which extent lexical access processes are shared across both tasks. Picture naming and auditory lexical decision are considered good tools for studying lexical access. Both of them are speeded tasks. Given these commonalities, another open question concerns the involvement of general cognitive abilities (e.g., processing speed) in both linguistic tasks. In the present study, we addressed these questions. We tested a large group of young adults enrolled in academic and vocational courses. Participants completed picture naming and auditory lexical decision tasks as well as a battery of tests assessing non-verbal processing speed, vocabulary, and non-verbal intelligence. Our results suggest that the lexical access processes involved in picture naming and lexical decision are related but less closely than one might have thought. Moreover, reaction times in picture naming and lexical decision depended as least as much on general processing speed as on domain-specific linguistic processes (i.e., lexical access processes).

Abstract

This resource contains data from 112 Dutch adults (18–29 years of age) who completed the Individual Differences in Language Skills test battery that included 33 behavioural tests assessing language skills and domain-general cognitive skills likely involved in language tasks. The battery included tests measuring linguistic experience (e.g. vocabulary size, prescriptive grammar knowledge), general cognitive skills (e.g. working memory, non-verbal intelligence) and linguistic processing skills (word production/comprehension, sentence production/comprehension). Testing was done in a lab-based setting resulting in high quality data due to tight monitoring of the experimental protocol and to the use of software and hardware that were optimized for behavioural testing. Each participant completed the battery twice (i.e., two test days of four hours each). We provide the raw data from all tests on both days as well as pre-processed data that were used to calculate various reliability measures (including internal consistency and test-retest reliability). We encourage other researchers to use this resource for conducting exploratory and/or targeted analyses of individual differences in language and general cognitive skills.

Abstract

A main challenge for theories of embodied cognition is to understand the task dependency of embodied language processing. One possibility is that perceptual representations (e.g., typical colour of objects mentioned in spoken sentences) are not activated routinely but the influence of perceptual representation emerges only when context strongly supports their involvement in language. To explore this question, we tested the effects of colour representations during language processing in three visual- world eye-tracking experiments. On critical trials, participants listened to sentence- embedded words associated with a prototypical colour (e.g., ‘...spinach...’) while they inspected a visual display with four printed words (Experiment 1), coloured or greyscale line drawings (Experiment 2) and a ‘blank screen’ after a preview of coloured or greyscale line drawings (Experiment 3). Visual context always presented a word/object (e.g., frog) associated with the same prototypical colour (e.g. green) as the spoken target word and three distractors. When hearing spinach participants did not prefer the written word frog compared to other distractor words (Experiment 1). In Experiment 2, colour competitors attracted more overt attention compared to average distractors, but only for the coloured condition and not for greyscale trials. Finally, when the display was removed at the onset of the sentence, and in contrast to the previous blank-screen experiments with semantic competitors, there was no evidence of colour competition in the eye-tracking record (Experiment 3). These results fit best with the notion that the main role of perceptual representations in language processing is to contextualize language in the immediate environment.

Abstract

An important issue in theories of word learning is how abstract or context-specific representations of novel words are. One aspect of this broad issue is how well learners maintain information about the source of novel words. We investigated whether listeners’ source memory was better for words learned from members of their in-group (students of their own university) than it is for words learned from members of an out-group (students from another institution). In the first session, participants saw 6 faces and learned which of the depicted students attended either their own or a different university. In the second session, they learned competing labels (e.g., citrus-peller and citrus-schiller; in English, lemon peeler and lemon stripper) for novel gadgets, produced by the in-group and out-group speakers. Participants were then tested for source memory of these labels and for the strength of their in-group bias, that is, for how much they preferentially process in-group over out-group information. Analyses of source memory accuracy demonstrated an interaction between speaker group membership status and participants’ in-group bias: Stronger in-group bias was associated with less accurate source memory for out-group labels than in-group labels. These results add to the growing body of evidence on the importance of social variables for adult word learning.

Abstract

There is a range of variability in the speed with which a single speaker will produce the same word from one instance to another. Individual differences studies have shown that the speed of production and the ability to maintain attention are related. This study investigated whether fluctuations in production latencies can be explained by spontaneous fluctuations in speakers' attention just prior to initiating speech planning. A relationship between individuals' incidental attentional state and response performance is well attested in visual perception, with lower prestimulus alpha power associated with faster manual responses. Alpha is thought to have an inhibitory function: Low alpha power suggests less inhibition of a specific brain region, whereas high alpha power suggests more inhibition. Does the same relationship hold for cognitively demanding tasks such as word production? In this study, participants named pictures while EEG was recorded, with alpha power taken to index an individual's momentary attentional state. Participants' level of alpha power just prior to picture presentation and just prior to speech onset predicted subsequent naming latencies. Specifically, higher alpha power in the motor system resulted in faster speech initiation. Our results suggest that one index of a lapse of attention during speaking is reduced inhibition of motor-cortical regions: Decreased motor-cortical alpha power indicates reduced inhibition of this area while early stages of production planning unfold, which leads to increased interference from motor-cortical signals and longer naming latencies. This study shows that the language production system is not impermeable to the influence of attention.

Abstract

In conversation, speech planning can overlap with listening to the interlocutor. It has been
postulated that once there is enough information to formulate a response, planning is initiated
and the response is maintained in working memory. Concurrently, the auditory input is
monitored for the turn end such that responses can be launched promptly. In three EEG
experiments, we aimed to identify the neural signature of phonological planning and monitoring
by comparing delayed responding to not responding (reading aloud, repetition and lexical
decision). These comparisons consistently resulted in a sustained positivity and beta power
reduction over posterior regions. We argue that these effects reflect attention to the sequence
end. Phonological planning and maintenance were not detected in the neural signature even
though it is highly likely these were taking place. This suggests that EEG must be used cautiously
to identify response planning when the neural signal is overridden by attention effects

Abstract

Understanding spoken language requires the integration and weighting of multiple cues, and may call on cue integration mechanisms that have been studied in other areas of perception. In the current study, we used eye-tracking (visual-world paradigm) to examine how contextual speech rate (a lower-level, perceptual cue) and morphosyntactic knowledge (a higher-level, linguistic cue) are iteratively combined and integrated. Results indicate that participants used contextual rate information immediately, which we interpret as evidence of perceptual inference and the generation of predictions about upcoming morphosyntactic information. Additionally, we observed that early rate effects remained active in the presence of later conflicting lexical information. This result demonstrates that (1) contextual speech rate functions as a cue to morphosyntactic inferences, even in the presence of subsequent disambiguating information; and (2) listeners iteratively use multiple sources of information to draw inferences and generate predictions during speech comprehension. We discuss the implication of these demonstrations for theories of language processing

Abstract

During spoken language comprehension, listeners make use of both knowledge-based and signal-based sources of information, but little is known about how cues from these distinct levels of representational hierarchy are weighted and integrated online. In an eye-tracking experiment using the visual world paradigm, we investigated the flexible weighting and integration of morphosyntactic gender marking (a knowledge-based cue) and contextual speech rate (a signal-based cue). We observed that participants used the morphosyntactic cue immediately to make predictions about upcoming referents, even in the presence of uncertainty about the cue’s reliability. Moreover, we found speech rate normalization effects in participants’ gaze patterns even in the presence of preceding morphosyntactic information. These results demonstrate that cues are weighted and integrated flexibly online, rather than adhering to a strict hierarchy. We further found rate normalization effects in the looking behavior of participants who showed a strong behavioral preference for the morphosyntactic gender cue. This indicates that rate normalization effects are robust and potentially automatic. We discuss these results in light of theories of cue integration and the two-stage model of acoustic context effects

Abstract

Neural oscillations track linguistic information during speech comprehension (e.g., Ding et al., 2016; Keitel et al., 2018), and are known to be modulated by acoustic landmarks and speech intelligibility (e.g., Doelling et al., 2014; Zoefel & VanRullen, 2015). However, studies investigating linguistic tracking have either relied on non-naturalistic isochronous stimuli or failed to fully control for prosody. Therefore, it is still unclear whether low frequency activity tracks linguistic structure during natural speech, where linguistic structure does not follow such a palpable temporal pattern. Here, we measured electroencephalography (EEG) and manipulated the presence of semantic and syntactic information apart from the timescale of their occurrence, while carefully controlling for the acoustic-prosodic and lexical-semantic information in the signal. EEG was recorded while 29 adult native speakers (22 women, 7 men) listened to naturally-spoken Dutch sentences, jabberwocky controls with morphemes and sentential prosody, word lists with lexical content but no phrase structure, and backwards acoustically-matched controls. Mutual information (MI) analysis revealed sensitivity to linguistic content: MI was highest for sentences at the phrasal (0.8-1.1 Hz) and lexical timescale (1.9-2.8 Hz), suggesting that the delta-band is modulated by lexically-driven combinatorial processing beyond prosody, and that linguistic content (i.e., structure and meaning) organizes neural oscillations beyond the timescale and rhythmicity of the stimulus. This pattern is consistent with neurophysiologically inspired models of language comprehension (Martin, 2016, 2020; Martin & Doumas, 2017) where oscillations encode endogenously generated linguistic content over and above exogenous or stimulus-driven timing and rhythm information.

Abstract

This study attempts to reveal the mechanisms behind the online formation of Wh-Filler-Gap Dependencies (WhFGD). Specifically, we aim to uncover the way in which maintenance and retrieval work in WhFGD processing, by paying special attention to the information that is retrieved when the gap is recognized. We use the agreement attraction phenomenon (Wagers, M. W., Lau, E. F., & Phillips, C. (2009). Agreement attraction in comprehension: Representations and processes. Journal of Memory and Language, 61(2), 206-237) as a probe. The first and second experiments examined the type of information that is maintained and how maintenance is motivated, investigating the retrieved information at the gap for reactivated fillers and definite NPs. The third experiment examined the role of the retrieval, comparing reactivated and active fillers. We contend that the information being accessed reflects the extent to which the filler is maintained, where the reader is able to access fine-grained information including category information as well as a representation of both the head and the modifier at the verb.

Abstract

In everyday conversation, turns often follow each other immediately or overlap in time. It has been proposed that speakers achieve this tight temporal coordination between their turns by engaging in linguistic dual-tasking, i.e., by beginning to plan their utterance during the preceding turn. This raises the question of how speakers manage to co-ordinate speech planning and listening with each other. Experimental work addressing this issue has mostly concerned the capacity demands and interference arising when speakers retrieve some content words while listening to others. However, many contributions to conversations are not content words, but backchannels, such as “hm”. Backchannels do not provide much conceptual content and are therefore easy to plan and respond to. To estimate how much they might facilitate speech planning in conversation, we determined their frequency in a Dutch and a German corpus of conversational speech. We found that 19% of the contributions in the Dutch corpus, and 16% of contributions in the German corpus were backchannels. In addition, many turns began with fillers or particles, most often translation equivalents of “yes” or “no,” which are likewise easy to plan.We proposed that to generate comprehensive models of using language in conversation psycholinguists should study not only the generation and processing of content words, as is commonly done, but also consider backchannels, fillers, and particles.

Abstract

Recent neuroimaging evidence suggests that the frequency of entrained oscillations in auditory cortices influences the perceived duration of speech segments, impacting word perception (Kösem et al. 2018). We further tested the causal influence of neural entrainment frequency during speech processing, by manipulating entrainment with continuous transcranial alternating
current stimulation (tACS) at distinct oscillatory frequencies (3 Hz and 5.5 Hz) above the auditory cortices. Dutch participants listened to speech and were asked to report their percept of a target Dutch word, which contained a vowel with an ambiguous duration. Target words
were presented either in isolation (first experiment) or at the end of spoken sentences (second experiment). We predicted that the tACS frequency would influence neural entrainment and
therewith how speech is perceptually sampled, leading to a perceptual over- or underestimation of the vowel’s duration. Whereas results from Experiment 1 did not confirm this prediction, results from experiment 2 suggested a small effect of tACS frequency on target word
perception: Faster tACS lead to more long-vowel word percepts, in line with the previous neuroimaging findings. Importantly, the difference in word perception induced by the different tACS frequencies was significantly larger in experiment 1 vs. experiment 2, suggesting that the
impact of tACS is dependent on the sensory context. tACS may have a stronger effect on spoken word perception when the words are presented in continuous speech as compared to when they are isolated, potentially because prior (stimulus-induced) entrainment of brain oscillations
might be a prerequisite for tACS to be effective.

Abstract

Successful communication is important for both society and people’s personal life. Here we show that people can improve their communication skills by interacting with multiple others, and that this improvement seems to come about by a greater tendency to take the addressee’s perspective when there are multiple partners. In Experiment 1, during a training phase, participants described figures to a new partner in each round or to the same partner in all rounds. Then all participants interacted with a new partner and their recordings from that round were presented to naïve listeners. Participants who had interacted with multiple partners during training were better understood. This occurred despite the fact that the partners had not provided the participants with any input other than feedback on comprehension during the interaction. In Experiment 2, participants were asked to provide descriptions to a different future participant in each round or to the same future participant in all rounds. Next they performed a surprise memory test designed to tap memory for global details, in line with the addressee’s perspective. Those who had provided descriptions for multiple future participants performed better. These results indicate that people can improve their communication skills by interacting with multiple people, and that this advantage might be due to a greater tendency to take the addressee’s perspective in such cases. Our findings thus show how the social environment can influence our communication skills by shaping our own behavior during interaction in a manner that promotes the development of our communication skills.

Abstract

To comprehend speech sounds, listeners tune in to speech rate information in the proximal (immediately adjacent), distal (non-adjacent), and global context (further removed preceding and following sentences). Effects of global contextual speech rate cues on speech perception have been shown to follow constraints not found for proximal and distal speech rate. Therefore, listeners may process such global cues at distinct time points during word recognition. We conducted a printed-word eye-tracking experiment to compare the time courses of distal and global rate effects. Results indicated that the distal rate effect emerged immediately after target sound presentation, in line with a general-auditory account. The global rate effect, however, arose more than 200 ms later than the distal rate effect, indicating that distal and global context effects involve distinct processing mechanisms. Results are interpreted in a two-stage model of acoustic context effects. This model posits that distal context effects involve very early perceptual processes, while global context effects arise at a later stage, involving cognitive adjustments conditioned by higher-level information.

Abstract

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.

Abstract

Composing sentence meaning is easier for predictable words than for unpredictable words. Are predictable words genuinely predicted, or simply more plausible and therefore easier to integrate with sentence context? We addressed this persistent and fundamental question using data from a recent, large-scale (N = 334) replication study, by investigating the effects of word predictability and sentence plausibility on the N400, the brain’s electrophysiological index of semantic processing. A spatiotemporally fine-grained mixed-effects multiple regression analysis revealed overlapping effects of predictability and plausibility on the N400, albeit with distinct spatiotemporal profiles. Our results challenge the view that the predictability-dependent N400 reflects the effects of either prediction or integration, and suggest that semantic facilitation of predictable words arises from a cascade of processes that activate and integrate word meaning with context into a sentence-level meaning.

Abstract

Social network structure has been argued to shape the structure of languages, as well as affect the spread of innovations and the formation of conventions in the community. Specifically, theoretical and computational models of language change predict that sparsely connected communities develop more systematic languages, while tightly knit communities can maintain high levels of linguistic complexity and variability. However, the role of social network structure in the cultural evolution of languages has never been tested experimentally. Here, we present results from a behavioral group communication study, in which we examined the formation of new languages created in the lab by micro‐societies that varied in their network structure. We contrasted three types of social networks: fully connected, small‐world, and scale‐free. We examined the artificial languages created by these different networks with respect to their linguistic structure, communicative success, stability, and convergence. Results did not reveal any effect of network structure for any measure, with all languages becoming similarly more systematic, more accurate, more stable, and more shared over time. At the same time, small‐world networks showed the greatest variation in their convergence, stabilization, and emerging structure patterns, indicating that network structure can influence the community's susceptibility to random linguistic changes (i.e., drift).

Abstract

That speakers can vary their speaking rate is evident, but how they accomplish this has hardly been studied. Consider this analogy: When walking, speed can be continuously increased, within limits, but to speed up further, humans must run. Are there multiple qualitatively distinct speech “gaits” that resemble walking and running? Or is control achieved by continuous modulation of a single gait? This study investigates these possibilities through simulations of a new connectionist computational model of the cognitive process of speech production, EPONA, that borrows from Dell, Burger, and Svec’s (1997) model. The model has parameters that can be adjusted to fit the temporal characteristics of speech at different speaking rates. We trained the model on a corpus of disyllabic Dutch words produced at different speaking rates. During training, different clusters of parameter values (regimes) were identified for different speaking rates. In a 1-gait system, the regimes used to achieve fast and slow speech are qualitatively similar, but quantitatively different. In a multiple gait system, there is no linear relationship between the parameter settings associated with each gait, resulting in an abrupt shift in parameter values to move from speaking slowly to speaking fast. After training, the model achieved good fits in all three speaking rates. The parameter settings associated with each speaking rate were not linearly related, suggesting the presence of cognitive gaits. Thus, we provide the first computationally explicit account of the ability to modulate the speech production system to achieve different speaking styles.

Abstract

Difficulties in saying the right word at the right time arise at least in part because multiple response candidates are simultaneously activated in the speaker’s mind. The word selection process has been simulated using the picture–word interference task, in which participants name pictures while ignoring a superimposed written distractor word. However, words are usually produced in context, in the service of achieving a communicative goal. Two experiments addressed the questions whether context influences word production, and if so, how. We embedded the picture–word interference task in a dialogue-like setting, in which participants heard a question and named a picture as an answer to the question while ignoring a superimposed distractor word. The conversational context was either constraining or nonconstraining towards the answer. Manipulating the relationship between the picture name and the distractor, we focused on two core processes of word production: retrieval of semantic representations (Experiment 1) and phonological encoding (Experiment 2). The results of both experiments showed that naming reaction times (RTs) were shorter when preceded by constraining contexts as compared with nonconstraining contexts. Critically, constraining contexts decreased the effect of semantically related distractors but not the effect of phonologically related distractors. This suggests that conversational contexts can help speakers with aspects of the meaning of to-be-produced words, but phonological encoding processes still need to be performed as usual.

Abstract

In everyday conversation, interlocutors often plan their utterances while listening to their conversational partners, thereby achieving short gaps between their turns. Important issues for current psycholinguistics are how interlocutors distribute their attention between listening and speech planning and how speech planning is timed relative to listening. Laboratory studies addressing these issues have used a variety of paradigms, some of which have involved using recorded speech to which participants responded, whereas others have involved interactions with confederates. This study investigated how this variation in the speech input affected the participants’ timing of speech planning. In Experiment 1, participants responded to utterances produced by a confederate, who sat next to them and looked at the same screen. In Experiment 2, they responded to recorded utterances of the same confederate. Analyses of the participants’ speech, their eye movements, and their performance in a concurrent tapping task showed that, compared with recorded speech, the presence of the confederate increased the processing load for the participants, but did not alter their global sentence planning strategy. These results have implications for the design of psycholinguistic experiments and theories of listening and speaking in dyadic settings.

Abstract

This neuroimaging study investigated the neural infrastructure of sentence-level language production. We compared brain activation patterns, as measured with BOLD-fMRI, during production of sentences that differed in verb argument structures (intransitives, transitives, ditransitives) and the lexical status of the verb (known verbs or pseudoverbs). The experiment consisted of 30 mini-blocks of six sentences each. Each mini-block started with an example for the type of sentence to be produced in that block. On each trial in the mini-blocks, participants were first given the (pseudo-)verb followed by three geometric shapes to serve as verb arguments in the sentences. Production of sentences with known verbs yielded greater activation compared to sentences with pseudoverbs in the core language network of the left inferior frontal gyrus, the left posterior middle temporalgyrus, and a more posterior middle temporal region extending into the angular gyrus, analogous to effects observed in language comprehension. Increasing the number of verb arguments led to greater activation in an overlapping left posterior middle temporal gyrus/angular gyrus area, particularly for known verbs, as well as in the bilateral precuneus. Thus, producing sentences with more complex structures using existing verbs leads to increased activation in the language network, suggesting some reliance on memory retrieval of stored lexical–syntactic information during sentence production. This study thus provides evidence from sentence-level language production in line with functional models of the language network that have so far been mainly based on single-word production, comprehension, and language processing in aphasia.

Abstract

Purpose: A recent behavioural experiment featuring a noise masking paradigm suggests that Apraxia of Speech (AOS) reflects a disruption of feedforward control, whereas feedback control is spared and plays a more prominent role in achieving and maintaining segmental contrasts. The present study set out to validate the interpretation of AOS as a possible feedforward impairment using computational neural modelling with the DIVA (Directions Into Velocities of Articulators) model.

Method: In a series of computational simulations with the DIVA model featuring a noise-masking paradigm mimicking the behavioural experiment, we investigated the effect of a feedforward, feedback, feedforward + feedback, and an upper motor neuron dysarthria impairment on average vowel spacing and dispersion in the production of six/bVt/speech targets.

Result: The simulation results indicate that the output of the model with the simulated feedforward deficit resembled the group findings for the human speakers with AOS best.

Conclusion: These results provide support to the interpretation of the human observations, corroborating the notion that AOS can be conceptualised as a deficit in feedforward control.

Abstract

Fluency is an important part of research on second language learning, but most research on language proficiency typically has not included oral fluency as part of interaction, even though natural communication usually occurs in conversations. The present study considered aspects of turn-taking behavior as part of the construct of fluency and investigated whether these aspects differentially influence perceived fluency ratings of native and non-native speech. Results from two experiments using acoustically manipulated speech showed that, in native speech, too ‘eager’ (interrupting a question with a fast answer) and too ‘reluctant’ answers (answering slowly after a long turn gap) negatively affected fluency ratings. However, in non-native speech, only too ‘reluctant’ answers led to lower fluency ratings. Thus, we demonstrate that acoustic properties of dialogue are perceived as part of fluency. By adding to our current understanding of dialogue fluency, these lab-based findings carry implications for language teaching and assessment

Abstract

A major debate in psycholinguistics concerns the representation of morphological structure in the mental lexicon. We report the results of an auditory primed lexical decision experiment in which we tested whether verbs prime their nominalizations in Dutch. We find morphological priming effects with regular nominalizations (schorsen ‘suspend’ → schorsing ‘suspension’) as well as with irregular nominalizations (schieten ‘shoot’ → schot ‘shot’). On this basis, we claim that, despite the lack of phonological identity between stem and derivation in the case of irregular nominalizations, the morphological relation between the two forms, suffices to evoke a priming effect. However, an alternative explanation, according to which the semantic relation in combination with the phonological overlap accounts for the priming effect, cannot be excluded