Hans Rutger Bosker

Publications

Displaying 1 - 6 of 6
  • Bosker, H. R., & Ghitza, O. (2018). Entrained theta oscillations guide perception of subsequent speech: Behavioral evidence from rate normalization. Language, Cognition and Neuroscience, 33(8), 955-967. doi:10.1080/23273798.2018.1439179.

    Abstract

    This psychoacoustic study provides behavioral evidence that neural entrainment in the theta range (3-9 Hz) causally shapes speech perception. Adopting the ‘rate normalization’ paradigm (presenting compressed carrier sentences followed by uncompressed target words), we show that uniform compression of a speech carrier to syllable rates inside the theta range influences perception of subsequent uncompressed targets, but compression outside theta range does not. However, the influence of carriers – compressed outside theta range – on target perception is salvaged when carriers are ‘repackaged’ to have a packet rate inside theta. This suggests that the brain can only successfully entrain to syllable/packet rates within theta range, with a causal influence on the perception of subsequent speech, in line with recent neuroimaging data. Thus, this study points to a central role for sustained theta entrainment in rate normalization and contributes to our understanding of the functional role of brain oscillations in speech perception.
  • Bosker, H. R. (2018). Putting Laurel and Yanny in context. The Journal of the Acoustical Society of America, 144(6), EL503-EL508. doi:10.1121/1.5070144.

    Abstract

    Recently, the world’s attention was caught by an audio clip that was perceived as “Laurel” or “Yanny”. Opinions were sharply split: many could not believe others heard something different from their perception. However, a crowd-source experiment with >500 participants shows that it is possible to make people hear Laurel, where they previously heard Yanny, by manipulating preceding acoustic context. This study is not only the first to reveal within-listener variation in Laurel/Yanny percepts, but also to demonstrate contrast effects for global spectral information in larger frequency regions. Thus, it highlights the intricacies of human perception underlying these social media phenomena.
  • Bosker, H. R., & Cooke, M. (2018). Talkers produce more pronounced amplitude modulations when speaking in noise. The Journal of the Acoustical Society of America, 143(2), EL121-EL126. doi:10.1121/1.5024404.

    Abstract

    Speakers adjust their voice when talking in noise (known as Lombard speech), facilitating speech comprehension. Recent neurobiological models of speech perception emphasize the role of amplitude modulations in speech-in-noise comprehension, helping neural oscillators to ‘track’ the attended speech. This study tested whether talkers produce more pronounced amplitude modulations in noise. Across four different corpora, modulation spectra showed greater power in amplitude modulations below 4 Hz in Lombard speech compared to matching plain speech. This suggests that noise-induced speech contains more pronounced amplitude modulations, potentially helping the listening brain to entrain to the attended talker, aiding comprehension.
  • Kösem, A., Bosker, H. R., Takashima, A., Meyer, A. S., Jensen, O., & Hagoort, P. (2018). Neural entrainment determines the words we hear. Current Biology, 28, 2867-2875. doi:10.1016/j.cub.2018.07.023.

    Abstract

    Low-frequency neural entrainment to rhythmic input has been hypothesized as a canonical mechanism that shapes sensory perception in time. Neural entrainment is deemed particularly relevant for speech analysis, as it would contribute to the extraction of discrete linguistic elements from continuous acoustic signals. However, its causal influence in speech perception has been difficult to establish. Here, we provide evidence that oscillations build temporal predictions about the duration of speech tokens that affect perception. Using magnetoencephalography (MEG), we studied neural dynamics during listening to sentences that changed in speech rate. Weobserved neural entrainment to preceding speech rhythms persisting for several cycles after the change in rate. The sustained entrainment was associated with changes in the perceived duration of the last word’s vowel, resulting in the perception of words with different meanings. These findings support oscillatory models of speech processing, suggesting that neural oscillations actively shape speech perception.
  • Maslowski, M., Meyer, A. S., & Bosker, H. R. (2018). Listening to yourself is special: Evidence from global speech rate tracking. PLoS One, 13(9): e0203571. doi:10.1371/journal.pone.0203571.

    Abstract

    Listeners are known to use adjacent contextual speech rate in processing temporally ambiguous speech sounds. For instance, an ambiguous vowel between short /A/ and long /a:/ in Dutch sounds relatively long (i.e., as /a:/) embedded in a fast precursor sentence, but short in a slow sentence. Besides the local speech rate, listeners also track talker-specific global speech rates. However, it is yet unclear whether other talkers' global rates are encoded with reference to a listener's self-produced rate. Three experiments addressed this question. In Experiment 1, one group of participants was instructed to speak fast, whereas another group had to speak slowly. The groups were compared on their perception of ambiguous /A/-/a:/ vowels embedded in neutral rate speech from another talker. In Experiment 2, the same participants listened to playback of their own speech and again evaluated target vowels in neutral rate speech. Neither of these experiments provided support for the involvement of self-produced speech in perception of another talker's speech rate. Experiment 3 repeated Experiment 2 but with a new participant sample that was unfamiliar with the participants from Experiment 2. This experiment revealed fewer /a:/ responses in neutral speech in the group also listening to a fast rate, suggesting that neutral speech sounds slow in the presence of a fast talker and vice versa. Taken together, the findings show that self-produced speech is processed differently from speech produced by others. They carry implications for our understanding of the perceptual and cognitive mechanisms involved in rate-dependent speech perception in dialogue settings.
  • Van Bergen, G., & Bosker, H. R. (2018). Linguistic expectation management in online discourse processing: An investigation of Dutch inderdaad 'indeed' and eigenlijk 'actually'. Journal of Memory and Language, 103, 191-209. doi:10.1016/j.jml.2018.08.004.

    Abstract

    Interpersonal discourse particles (DPs), such as Dutch inderdaad (≈‘indeed’) and eigenlijk (≈‘actually’) are highly frequent in everyday conversational interaction. Despite extensive theoretical descriptions of their polyfunctionality, little is known about how they are used by language comprehenders. In two visual world eye-tracking experiments involving an online dialogue completion task, we asked to what extent inderdaad, confirming an inferred expectation, and eigenlijk, contrasting with an inferred expectation, influence real-time understanding of dialogues. Answers in the dialogues contained a DP or a control adverb, and a critical discourse referent was replaced by a beep; participants chose the most likely dialogue completion by clicking on one of four referents in a display. Results show that listeners make rapid and fine-grained situation-specific inferences about the use of DPs, modulating their expectations about how the dialogue will unfold. Findings further specify and constrain theories about the conversation-managing function and polyfunctionality of DPs.

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