Publications

Abstract

We utilized the N400 effect to investigate the influence of speech register on predictive language processing. Participants listened to long stretches (4 – 15 min) of naturalistic speech from different registers (dialogues, news broadcasts, and read-aloud books), totalling approximately 50,000 words, while the EEG signal was recorded. We estimated the surprisal of words in the speech materials with the aid of a statistical language model in such a manner that it reflected different predictive processing strategies; generic, register-specific, or recency-based. The N400 amplitude was best predicted with register-specific word surprisal, indicating that the statistics of the wider context (i.e., register) influences predictive language processing. Furthermore, adaptation to speech register cannot merely be explained by recency effects; instead, listeners adapt their word anticipations to the presented speech register.

Abstract

We present a dataset of behavioural and fMRI observations acquired in the context of humans involved in multimodal referential communication. The dataset contains audio/video and motion-tracking recordings of face-to-face, task-based communicative interactions in Dutch, as well as behavioural and neural correlates of participants’ representations of dialogue referents. Seventy-one pairs of unacquainted participants performed two interleaved interactional tasks in which they described and located 16 novel geometrical objects (i.e., Fribbles) yielding spontaneous interactions of about one hour. We share high-quality video (from three cameras), audio (from head-mounted microphones), and motion-tracking (Kinect) data, as well as speech transcripts of the interactions. Before and after engaging in the face-to-face communicative interactions, participants’ individual representations of the 16 Fribbles were estimated. Behaviourally, participants provided a written description (one to three words) for each Fribble and positioned them along 29 independent conceptual dimensions (e.g., rounded, human, audible). Neurally, fMRI signal evoked by each Fribble was measured during a one-back working-memory task. To enable functional hyperalignment across participants, the dataset also includes fMRI measurements obtained during visual presentation of eight animated movies (35 minutes total). We present analyses for the various types of data demonstrating their quality and consistency with earlier research. Besides high-resolution multimodal interactional data, this dataset includes different correlates of communicative referents, obtained before and after face-to-face dialogue, allowing for novel investigations into the relation between communicative behaviours and the representational space shared by communicators. This unique combination of data can be used for research in neuroscience, psychology, linguistics, and beyond.

Abstract

Speech produced in noise (Lombard speech) is more intelligible than speech produced in quiet (plain speech). Previous research on the Lombard intelligibility benefit focused almost entirely on how native speakers produce and perceive Lombard speech. In this study, we investigate the size of the Lombard intelligibility benefit of both native (American-English) and non-native (native Dutch) English for native and non-native listeners (Dutch and Spanish). We used a glimpsing metric to measure the energetic masking potential of speech, which predicted that both native and non-native Lombard speech could withstand greater amounts of masking to a similar extent, compared to plain speech. In an intelligibility experiment, native English, Spanish, and Dutch listeners listened to the same words, mixed with noise. While the non-native listeners appeared to benefit more from Lombard speech than the native listeners did, each listener group experienced a similar benefit for native and non-native Lombard speech. Energetic masking, as captured by the glimpsing metric, only accounted for part of the Lombard benefit, indicating that the Lombard intelligibility benefit does not only result from a shift in spectral distribution. Despite subtle native language influences on non-native Lombard speech, both native and non-native speech provides a Lombard benefit.

Abstract

Distributional semantic models capture word-level meaning that is useful in many natural language processing tasks and have even been shown to capture cognitive aspects of word meaning. The majority of these models are purely text based, even though the human sensory experience is much richer. In this paper we create visually grounded word embeddings by combining English text and images and compare them to popular text-based methods, to see if visual information allows our model to better capture cognitive aspects of word meaning. Our analysis shows that visually grounded embedding similarities are more predictive of the human reaction times in a large priming experiment than the purely text-based embeddings. The visually grounded embeddings also correlate well with human word similarity ratings.Importantly, in both experiments we show that he grounded embeddings account for a unique portion of explained variance, even when we include text-based embeddings trained on huge corpora. This shows that visual grounding allows our model to capture information that cannot be extracted using text as the only source of information.

Abstract

This study compares the role of exemplars in native and non-native listening. Two English identity priming experiments were conducted with native English, Dutch non-native, and Spanish non-native listeners. In Experiment 1, primes and targets were spoken in the same or a different voice. Only the native listeners showed exemplar effects. In Experiment 2, primes and targets had the same or a different degree of vowel reduction. The Dutch, but not the Spanish, listeners were familiar with this reduction pattern from their L1 phonology. In this experiment, exemplar effects only arose for the Spanish listeners. We propose that in these lexical decision experiments the use of exemplars is co-determined by listeners’ available processing resources, which is modulated by the familiarity with the variation type from their L1 phonology. The use of exemplars differs between native and non-native listening, suggesting qualitative differences between native and non-native speech comprehension processes.

Abstract

Reduced forms like yeshay for yesterday often occur in conversations. Previous behavioral research reported a processing advantage for full over reduced forms. The present study investigated whether this processing advantage is reflected in a modulation of alpha (8–12 Hz) and gamma (30+ Hz) band activity. In three electrophysiological experiments, participants listened to full and reduced forms in isolation (Experiment 1), sentence-final position (Experiment 2), or mid-sentence position (Experiment 3). Alpha power was larger in response to reduced forms than to full forms, but only in Experiments 1 and 2. We interpret these increases in alpha power as reflections of higher auditory cognitive load. In all experiments, gamma power only increased in response to full forms, which we interpret as showing that lexical activation spreads more quickly through the semantic network for full than for reduced forms. These results confirm a processing advantage for full forms, especially in non-medial sentence position.

Abstract

Amsterdam klinkt in informele gesprekken vaak als Amsdam en Rotterdam als Rodam, zonder dat de meeste moedertaalsprekers zich daar bewust van zijn. In alledaagse situaties valt een aanzienlijk deel van de klanken weg. Daarnaast worden veel klanken zwakker gearticuleerd (bijvoorbeeld een d als een j, als de mond niet helemaal afgesloten wordt). Het lijkt waarschijnlijk dat deze half uitgesproken woorden een probleem vormen voor tweedetaalleerders. Gereduceerde vormen kunnen immers sterk afwijken van de vormen die deze leerders geleerd hebben. Of dit werkelijk zo is, hebben de auteurs onderzocht in twee studies. Voordat ze deze twee studies bespreken, vertellen ze eerst kort iets over de verschillende typen reducties die voorkomen.

Abstract

This paper combines two different approaches to modeling reaction time data from lexical decision experiments, viz. a dataoriented statistical analysis by means of a linear mixed effects model, and a process-oriented computational model of human speech comprehension. The linear mixed effect model is implemented by lmer in R. As computational model we apply DIANA, an end-to-end computational model which aims at modeling the cognitive processes underlying speech comprehension. DIANA takes as input the speech signal, and provides as output the orthographic transcription of the stimulus, a word/non-word judgment and the associated reaction time. Previous studies have shown that DIANA shows good results for large-scale lexical decision experiments in Dutch and North-American English. We investigate whether predictors that appear significant in an lmer analysis and processes implemented in DIANA can be related and inform both approaches. Predictors such as ‘previous reaction time’ can be related to a process description; other predictors, such as ‘lexical neighborhood’ are hard-coded in lmer and emergent in DIANA. The analysis focuses on the interaction between subject variables and task variables in lmer, and the ways in which these interactions can be implemented in DIANA.

Abstract

In spontaneous conversations, words are often produced in reduced form compared to formal careful speech. In English, for instance, ’probably’ may be pronounced as ’poly’ and ’police’ as ’plice’. Reduced forms are very common, and native listeners usually do not have any problems with interpreting these reduced forms in context. Non-native listeners, however, have great difficulties in comprehending reduced forms. In order to investigate the problems in comprehension that non-native listeners experience, a dictation experiment was conducted in which sentences were presented auditorily to non-natives either in full (unreduced) or reduced form. The types of errors made by the L2 listeners reveal aspects of the cognitive processes underlying this dictation task. In addition, we compare the errors made by these human participants with the type of word errors made by DIANA, a recently developed computational model of word comprehension.

Abstract

The majority of studies addressing psycholinguistic questions focus on speech produced and processed in a careful, laboratory speech style. This ‘careful’ speech is very different from the speech that listeners encounter in casual conversations. This article argues that research on casual speech is necessary to show the validity of conclusions based on careful speech. Moreover, research on casual speech produces new insights and questions on the processes underlying communication and on the mental lexicon that cannot be revealed by research using careful speech. This article first places research on casual speech in its historic perspective. It then provides many examples of how casual speech differs from careful speech and shows that these differences may have important implications for psycholinguistic theories. Subsequently, the article discusses the challenges that research on casual speech faces, which stem from the high variability of this speech style, its necessary casual context, and that casual speech is connected speech. We also present opportunities for research on casual speech, mostly in the form of new experimental methods that facilitate research on connected speech. However, real progress can only be made if these new methods are combined with advanced (still to be developed) statistical techniques.