Presentations

Abstract

Conversation often involves simultaneous production and comprehension, yet little research has investigated whether these two processes interfere with one another. We tested participants’ ability to dual-task with production and comprehension tasks. Task one (production task) was picture naming. Task two (comprehension task) was either syllable identification (linguistic condition) or tone identification (non-linguistic condition). The two identification tasks were matched for difficulty. Three SOAs (50ms, 300ms, and 1800ms) resulted in different amounts of overlap between the production and comprehension tasks. We hypothesized that as production and comprehension use similar resources there would be greater interference with concurrent linguistic than non-linguistic tasks.
At the 50ms SOA, picture naming latencies were slower in the linguistic compared to the non-linguistic condition, suggesting that the resources required for production and comprehension overlap more in the linguistic condition. As the syllables were non-words without lexical representations, this interference likely occurs primarily at the phonological level. Across all SOAs, identification RTs were longer in the linguistic condition, showing that such phonological interference percolates through to the comprehension task, regardless of SOA. In sum, these results demonstrate that concurrent access to the phonological level in production and comprehension results in measurable interference in both speaking and comprehending.

Abstract

Listeners are continuously exposed to a broad range of speech rates. Earlier work has shown that listeners perceive phonetic category boundaries relative to contextual speech rate. This process of rate-dependent speech perception has been suggested to occur across talker changes, with the speech rate of talker A influencing perception of talker B. This study tested whether a ‘global’ speech rate calculated over multiple talkers and over a longer period of time affected perception of the temporal Dutch vowel contrast /ɑ/-/a:/. First, Experiment 1 demonstrated that listeners more often reported hearing long /a:/ in fast contexts than in ‘neutral rate’ contexts, replicating earlier findings. Then, in Experiment 2, one participant group was exposed to ‘neutral’ speech from talker A intermixed with slow speech from talker B. Another group listened to the same ‘neutral’ speech from talker A, but to fast speech from talker B. Between-group comparison in the ‘neutral’ condition revealed that Group 1 reported more long /a:/ than Group 2, indicating that A’s ‘neutral’ speech sounded faster when B was slower. Finally, Experiment 3 tested whether talking at slow or fast rates oneself elicits the same ‘global’ rate effects. However, no evidence was found that self-produced speech modulated perception of talker A. This study corroborates the idea that ‘global’ rate-dependent effects occur across talkers, but are insensitive to one’s own speech rate. Results are interpreted in light of the general auditory mechanisms thought to underlie rate normalization, with implications for our understanding of dialogue.

Abstract

Speech rate is known to modulate perception of temporally ambiguous speech sounds. For instance, a vowel may be perceived as short when the immediate speech context is slow, but as long when the context is fast. Yet, effects of long-term tracking of speech rate are largely unexplored. Two experiments tested whether long-term tracking of rate influences perception of the temporal Dutch vowel contrast /A/-/a:/. In Experiment 1, one low-rate group listened to ‘neutral’ rate speech from talker A and to slow speech from talker B. Another high-rate group was exposed to the same neutral speech from A, but to fast speech from B. Between-group comparison of the ‘neutral’ trials revealed that the low-rate group reported a higher proportion of /a:/ in A’s ‘neutral’ speech, indicating that A sounded faster when B was slow. Experiment 2 tested whether one’s own speech rate also contributes to effects of long-term tracking of rate. Here, talker B’s speech was replaced by playback of participants’ own fast or slow speech. No evidence was found that one’s own voice affected perception of talker A in larger speech contexts. These results carry implications for our understanding of the mechanisms involved in rate-dependent speech perception and of dialogue.

Abstract

Speech rate is known to modulate perception of temporally ambiguous speech sounds. For instance, a vowel may be perceived as short when the immediate speech context is slow, but as long when the context is fast. Yet, effects of long-term tracking of speech rate are largely unexplored. Two experiments tested whether long-term tracking of rate influences perception of the temporal Dutch vowel contrast /ɑ/-/a:/. In Experiment 1, one low-rate group listened to 'neutral' rate speech from talker A and to slow speech from talker B. Another high-rate group was exposed to the same neutral speech from A, but to fast speech from B. Between-group comparison of the 'neutral' trials revealed that the low-rate group reported a higher proportion of /a:/ in A's 'neutral' speech, indicating that A sounded faster when B was slow. Experiment 2 tested whether one's own speech rate also contributes to effects of long-term tracking of rate. Here, talker B's speech was replaced by playback of participants' own fast or slow speech. No evidence was found that one's own voice affected perception of talker A in larger speech contexts. These results carry implications for our understanding of the mechanisms involved in rate-dependent speech perception and of dialogue.

Abstract

Speech can be produced at different rates. The ability to produce faster or slower speech may be thought to result from executive control processes enlisted to modulate lexical selection and phonological encoding stages of speech planning.

This study used simulations of the model of serial order in language by Dell, Burger and Svec (1997, DBS) to characterise the strategies adopted by speakers when naming pictures at fast, medium and slow prescribed rates. Our new implementation of DBS was able to produce activation patterns that correlated strongly with observed syllable-level timing of disyllabic words from this task.

For each participant, different speaking rates were associated with different regions of the DBS parameter space. The precise placement of the speaking rates in the parameter space differed markedly between participants. Participants applied broadly the same parameter manipulation to accelerate their speech. This was however not the case for deceleration. Hierarchical clustering revealed two distinct patterns of parameter adjustment employed to decelerate speech, suggesting that deceleration is not necessarily achieved by the inverse process of acceleration. In addition, potential refinements to the DBS model are discussed.

Abstract

Prominent theories of predictive language processing assume that language production processes are used to anticipate upcoming linguistic input during comprehension (Dell & Chang, 2014; Pickering & Garrod, 2013). Here, we explored the converse case: Does a task set including production in addition to comprehension encourage prediction, compared to a task only including comprehension? To test this hypothesis, participants carried out a cross-modal naming task (Exp 1a), a self-paced reading task (Exp1 b) that did not include overt production, and a task (Exp 1c) in which naming and reading trials were evenly interleaved. We used the same predictable (N = 40) and non-predictable (N = 40) sentences in all three tasks. The sentences consisted of a fixed agent, a transitive verb and a predictable or non-predictable target word (The man breaks a glass vs. The man borrows a glass). The mean cloze probability in the predictable sentences was .39 (ranging from .06 to .8; zero in the non-predictable sentences). A total of 162 volunteers took part in the experiment which was run in a between-participants design. In Exp 1a, fifty-four participants listened to recordings of the sentences which ended right before the spoken target word. Coinciding with the end of the playback, a picture of the target word was shown which the participants were asked to name as fast as possible. Analyses of their naming latencies revealed a statistically significant naming advantage of 108 ms on predictable over non-predictable trials. Moreover, we found that the objects’ naming advantage was predicted by the target words’ cloze probability in the sentences (r = .347, p = .038). In Exp 1b, 54 participants were asked to read the same sentences in a self-paced fashion. To allow for testing of potential spillover effects, we added a neutral prepositional phrase (breaks a glass from the collection/borrows a glass from the neighbor) to each sentence. The sentences were read word-by-word, advancing by pushing the space bar. On 30% of the trials, comprehension questions were used to keep up participants' focus on comprehending the sentences. Analyses of their spillover region reading times revealed a numerical advantage (8 ms; tspillover = -1.1, n.s.) in the predictable as compared to the non-predictable condition. Importantly, the analysis of participants' responses to the comprehension questions, showed that they understood the sentences (mean accuracy = 93%). In Exp 1c, the task comprised 50% naming trials and 50% reading trials which appeared in random order. Fifty-four participants named and read the same objects and sentences as in the previous versions. The results showed a naming advantage on predictable over non-predictable items (99 ms) and a positive correlation between the items’ cloze probability and their naming advantage (r = .322, p = .055). Crucially, the post-target reading time analysis showed that with naming trials and reading trials interleaved, there was also a statistically reliable prediction effect on reading trials. Participants were 19 ms faster at reading the spillover region on predictable relative to non-predictable items (tspillover = -2.624). To summarize, although we used the same sentences in all sub-experiments, we observed effects of prediction only when the task set involved production. In the reading only experiment (Exp 1b), no evidence for anticipation was obtained although participants clearly understood the sentences and the same sentences yielded reading facilitation when interleaved with naming trials (Exp 1c). This suggests that predictive language processing can be modulated by the comprehenders’ task set. When the task set involves language production, as is often the case in natural conversation, comprehenders appear to engage in prediction to a stronger degree than in pure comprehension tasks. In our discussion, we will discuss the notion that language production may engage prediction, because being able to predict words another person is about to say might optimize the comprehension process and enable smooth turn-taking.

Abstract

A substantial body of literature has shown that readers and listeners often anticipate information. An open question concerns the mechanisms underlying predictive language processing. Multiple mechanisms have been suggested. One proposal is that comprehenders use event knowledge to predict upcoming words. Other theoretical frameworks propose that predictions are made based on simple word associations. In a recent EEG study, Metusalem and colleagues reported evidence for the modulating influence of event knowledge on prediction. They examined the degree to which event knowledge is activated during sentence comprehension. Their participants read two sentences, establishing an event scenario, which were followed by a final sentence containing one of three target words: a highly expected word, a semantically unexpected word that was related to the described event, or a semantically unexpected and event-unrelated word (see Figure, for an example). Analyses of participants’ ERPs elicited by the target words revealed a three-way split with regard to the amplitude of the N400 elicited by the different types of target: the expected targets elicited the smallest N400, the unexpected and event-unrelated targets elicited the largest N400. Importantly, the amplitude of the N400 elicited by the unexpected but event-related targets was significantly attenuated relative to the amplitude of the N400 elicited by the unexpected and event-unrelated targets. Metusalem et al. concluded that event knowledge is immediately available to constrain on-line language processing. Based on a post-hoc analysis, the authors rejected the possibility that the results could be explained by simple word associations. In the present study, we addressed the role of simple word associations in discourse comprehension more directly. Specifically, we explored the contribution of associative priming to the graded N400 pattern seen in Metusalem et al’s study. We conducted two EEG experiments. In Experiment 1, we reran Metusalem and colleagues’ context manipulation and closely replicated their results. In Experiment 2, we selected two words from the event-establishing sentences which were most strongly associated with the unexpected but event-related targets in the final sentences. Each of the two associates was then placed in a neutral carrier sentence. We controlled that none of the other words in these carrier sentences was associatively related to the target words. Importantly, the two carrier sentences did not build up a coherent event. We recorded EEG while participants read the carrier sentences followed by the same final sentences as in Experiment 1. The results showed that as in Experiment 1 the amplitude of the N400 elicited by both types of unexpected target words was larger than the N400 elicited by the highly expected target. Moreover, we found a global tendency towards the critical difference between event-related and event-unrelated unexpected targets which reached statistical significance only at parietal electrodes over the right hemisphere. Because the difference between event-related and event-unrelated conditions was larger when the sentences formed a coherent event compared to when they did not, our results suggest that associative priming alone cannot account for the N400 pattern observed in our Experiment 1 (and in the study by Metusalem et al.). However, because part of the effect remained, probably due to associative facilitation, the findings demonstrate that during discourse reading both event knowledge activation and simple word associations jointly contribute to the prediction process. The results highlight that multiple mechanisms underlie predictive language processing.

Abstract

Janssen and Barber (2012) reported two studies on the production of complex noun phrases (Spanish and French noun-adjective and noun-noun phrases). They found that production latencies depended only on the frequencies of the phrases, but not on the frequencies of the individual words. This pattern may be seen as evidence for lexical storage of phrases and against the traditional “words & rules” view of the representation of linguistic knowledge. We will discuss a series of experiments on the production of Dutch adjective-noun phrases. We replicated the phrase frequency effect seen by Janssen and Barber, but also found a robust effect of the frequency of the first word of the phrase. We argue that the phrase frequency effect arises during the conceptual preparation of the utterance and that the results are consistent with the view that phrases are composed by combining individual words, in line with the “words & rules” view.

Abstract

Frequent and predictable words are generally pronounced with less effort and are therefore acoustically more reduced than less frequent or unpredictable words. Local predictability can be operationalised by Transitional Probability (TP), which indicates how likely a word is to occur given its immediate context. We investigated whether and how probabilistic reduction effects on word durations change with adult age when reading aloud content words embedded in sentences.
The results showed equally large frequency effects on verb and noun durations for both younger (Mage = 20 years) and older (Mage = 68 years) adults. Backward TP also affected word duration for younger and older adults alike. ForwardTP, however, had no significant effect on word duration in either age group.
Our results resemble earlier findings of more robust BackwardTP effects compared to ForwardTP effects. Furthermore, unlike often reported decline in predictive processing with aging, probabilistic reduction effects remain stable across adulthood.

Abstract

A recurring criticism in the field of psycholinguistics and is the lack of ecological validity of experimental designs. For example, many experiments on sentence comprehension are conducted enclosed booths, where sentences are presented word by word on a computer screen. In addition, very often participants are instructed to make judgments that relate directly to the experimental manipulation. Thus, the contexts in which these processes are studied is quite restricted, which calls into question the generalizability of the results to more naturalistic environments. A possible solution to this problem is the use of virtual reality (VR) in psycholinguistic experiments. By immersing participants into a virtual environment, ecological validity can be increased while experimental control is maintained.
In the current experiment we combine electroencephalography (EEG) and VR to look at semantic processing in a more naturalistic setting. During the experiment, participants move through a visually rich virtual restaurant. Tables and avatars are placed in the restaurant and participants are instructed to stop at each table and look at the object (e.g. a plate with a steak) in front of the avatar. Then, the avatar will produce an utterance to accompany the object (e.g. “I think this steak is very nice”), in which the noun will either match (e.g. steak) or mismatch (e.g. mandarin) with the item on the table. Based on previous research, we predict a modulation of the N400, which should be larger in the mismatch than the match condition. Implications of the use of virtual reality for experimental research will be discussed.

Abstract

Fluctuations in pupil size have been shown to reflect variations in processing demands during language
comprehension. Increases in pupil diameter have been observed as a consequence of syntactic anomalies
(Schluroff 1982), increased syntactic complexity (Just & Carpenter 1993) and lexical ambiguity (Ben-
Nun 1986). An issue that has not received attention is whether pupil size also varies due to pragmatic
manipulations. In a pupillometry experiment, we investigated whether pupil diameter is sensitive to
increased processing demands as a result of comprehending an indirect request versus a statement. During
natural conversation, communication is often indirect. For example, in an appropriate context, ''It'' cold in
here'' is a request to shut the window, rather than a statement about room temperature (Holtgraves 1994).
We tested 49 Dutch participants (mean age = 20.8). They were presented with 120 picture-sentence
combinations that could either be interpreted as an indirect request (a picture of a window with the
sentence ''it's hot here'') or as a statement (a picture of a window with the sentence ''it's nice here''). The
indirect requests were non-conventional, i.e. they did not contain directive propositional content and were
not directly related to the underlying felicity conditions (Holtgraves 2002). In order to verify that the
indirect requests were recognized, participants were asked to decide after each combination whether or
not they heard a request. Based on the hypothesis that understanding this type of indirect utterances
requires additional inferences to be made on the part of the listener (e.g., Holtgraves 2002; Searle 1975;
Van Ackeren et al. 2012), we predicted a larger pupil diameter for indirect requests than statements. The
data were analyzed using linear mixed-effects models in R, which allow for simultaneous inclusion of
participants and items as random factors (Baayen, Davidson, & Bates 2008). The results revealed a larger
mean pupil size and a larger peak pupil size for indirect requests as compared to statements. In line with
previous studies on pupil size and language comprehension (e.g., Just & Carpenter 1993), this difference
was observed within a 1.5 second window after critical word onset. We suggest that the increase in pupil
size reflects additional on-line processing demands for the comprehension of non-conventional indirect
requests as compared to statements. This supports the idea that comprehending this type of indirect
request requires capacity demanding inferencing on the part of the listener. In addition, this study
demonstrates the usefulness of pupillometry as a tool for experimental research in pragmatics.

Abstract

Fluctuations in pupil size have been shown to reflect variations in processing demands during language
comprehension. Increases in pupil diameter have been observed as a consequence of syntactic anomalies
(Schluroff 1982), increased syntactic complexity (Just & Carpenter 1993) and lexical ambiguity (Ben-
Nun 1986). An issue that has not received attention is whether pupil size also varies due to pragmatic
manipulations. In a pupillometry experiment, we investigated whether pupil diameter is sensitive to
increased processing demands as a result of comprehending an indirect request versus a statement. During
natural conversation, communication is often indirect. For example, in an appropriate context, ''It'' cold in
here'' is a request to shut the window, rather than a statement about room temperature (Holtgraves 1994).
We tested 49 Dutch participants (mean age = 20.8). They were presented with 120 picture-sentence
combinations that could either be interpreted as an indirect request (a picture of a window with the
sentence ''it's hot here'') or as a statement (a picture of a window with the sentence ''it's nice here''). The
indirect requests were non-conventional, i.e. they did not contain directive propositional content and were
not directly related to the underlying felicity conditions (Holtgraves 2002). In order to verify that the
indirect requests were recognized, participants were asked to decide after each combination whether or
not they heard a request. Based on the hypothesis that understanding this type of indirect utterances
requires additional inferences to be made on the part of the listener (e.g., Holtgraves 2002; Searle 1975;
Van Ackeren et al. 2012), we predicted a larger pupil diameter for indirect requests than statements. The
data were analyzed using linear mixed-effects models in R, which allow for simultaneous inclusion of
participants and items as random factors (Baayen, Davidson, & Bates 2008). The results revealed a larger
mean pupil size and a larger peak pupil size for indirect requests as compared to statements. In line with
previous studies on pupil size and language comprehension (e.g., Just & Carpenter 1993), this difference
was observed within a 1.5 second window after critical word onset. We suggest that the increase in pupil
size reflects additional on-line processing demands for the comprehension of non-conventional indirect
requests as compared to statements. This supports the idea that comprehending this type of indirect
request requires capacity demanding inferencing on the part of the listener. In addition, this study
demonstrates the usefulness of pupillometry as a tool for experimental research in pragmatics.