Presentations

Abstract

This study aims to test recent theoretical frameworks in speech motor control which claim that speech production targets are specified in auditory terms. According to such frameworks, people with better auditory acuity should have more precise speech targets. Participants performed speech perception and production tasks in a counterbalanced order. Speech perception acuity was assessed using an adaptive speech discrimination task, where participants discriminated between stimuli on a /ɪ/-/ɛ/ and a /ɑ/-/ɔ/ continuum. To assess variability in speech production, participants performed a pseudo-word reading task; formant values were measured for each recording of the vowels /ɪ/, /ɛ/, /ɑ/ and /ɔ/ in 288 pseudowords (18 per vowel, each of which was repeated 4 times). We predicted that speech production variability would correlate inversely with discrimination performance. Results confirmed this prediction as better discriminators had more distinctive vowel production targets. In addition, participants with higher auditory acuity produced vowels with smaller within-phoneme variability but spaced farther apart in vowel space. This study highlights the importance of individual differences in the study of speech motor control, and sheds light on speech production-perception interactions.

Abstract

This study aims to test a prediction of recent
theoretical frameworks in speech motor control: if
speech production targets are specified in auditory
terms, people with better auditory acuity should
have more precise speech targets.
To investigate this, we had participants perform
speech perception and production tasks in a
counterbalanced order. To assess speech perception
acuity, we used an adaptive speech discrimination
task. To assess variability in speech production,
participants performed a pseudo-word reading task;
formant values were measured for each recording.
We predicted that speech production variability to
correlate inversely with discrimination performance.
The results suggest that people do vary in their
production and perceptual abilities, and that better
discriminators have more distinctive vowel
production targets, confirming our prediction. This
study highlights the importance of individual
differences in the study of speech motor control, and
sheds light on speech production-perception
interaction.

Abstract

In investigations of feedback control during speech production, researchers have focused on two different kinds of responses to erroneous or unexpected auditory feedback. Compensation refers to online, feedback-based corrections of articulations. In contrast, adaptation refers to long-term changes in the speech production system after exposure to erroneous/unexpected feedback, which may last even after feedback is normal again. In the current study, we aimed to compare both types of feedback responses by investigating the conditions under which the system starts adapting in addition to merely compensating. Participants vocalized long vowels while they were exposed to either consistently altered auditory feedback, or to feedback that was unpredictably either altered or normal. Participants were not aware of the manipulation of auditory feedback. We predicted that both conditions would elicit compensation, whereas adaptation would be stronger when the altered feedback was consistent across trials. The results show that although there seems to be somewhat more adaptation for the consistently altered feedback condition, a substantial amount of individual variability led to statistically unreliable effects at the group level. The results stress the importance of taking into account individual differences and show that people vary widely in how they respond to altered auditory feedback.

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.