Spoken language achieves robustness and evolvability by exploiting degeneracy and neutrality

Tierney

2019

Preprint

| Prosody can be defined as the rhythm and intonation patterns spanning words, phrases and sentences. Accurate perception of prosody is an important component of many aspects of language processing, such as parsing grammatical structures, recognizing words, and determining where emphasis may be placed.Prosody perception is important for language acquisition and can be impaired in language-related developmental disorders. However, existing assessments of prosodic perception suffer from some shortcomings. These include being unsuitable for use with typically developing adults due to ceiling effects, or failing to allow the investigator to distinguish the unique contributions of individual acoustic features such as pitch and temporal cues. Here we present the Multi-Dimensional Battery of Prosody Perception (MBOPP), a novel tool for the assessment of prosody perception. It consists of two subtests --Linguistic Focus, which measures the ability to hear emphasis or sentential stress, and Phrase Boundaries, which measures the ability to hear where in a compound sentence one phrase ends, and another begins.Perception of individual acoustic dimensions (Pitch and Time) can be examined separately, and test difficulty can be precisely calibrated by the the experimenter because stimuli were created using a continuous voice morph space. We present validation analyses from a sample of 57 individuals and discuss how the battery might be deployed to examine perception of prosody in various populations.

Section: The Role Of Pitch and Durational Cues In Focus And Phrase Pesupporting

confidence: 90%

The Multidimensional Battery of Prosody Perception (MBOPP)

Tierney

2019

Preprint

“…An alternate explanation is that speech is robust to individual differences in auditory perception because it is structurally redundant: multiple acoustic dimensions convey information about a given category. This property may make speech robust not only to external background noise (Winter, 2014) but also to internal "noise" that is thought to relate to imprecise representation of an auditory dimension (Patel, 2014). This raises the possibility that listeners may be able to compensate for impairments along a single auditory dimension by assigning greater perceptual weight to auditory dimensions that they are better able to process.…”

Section: Speech Perception As Categorizationmentioning

confidence: 99%

Tailored perception: listeners’ strategies for perceiving speech fit their individual perceptual abilities

Holt

et al. 2018

Preprint

Communicative auditory signals express their structure through acoustic dimensions such as pitch and timing. Individuals' abilities to perceive these dimensions vary widely, and yet most people seem to comprehend music and speech easily. How?Here we tested whether redundancy -multiple acoustic cues indexing the same feature -makes music and speech robust to such individual differences. A model population with a severe and specific deficit for perceiving pitch (congenital amusics) and controls completed 3 tasks, each testing whether they could take advantage of redundancy. In each task, performance relied on either pitch or duration perception alone, or both together redundantly. Results showed that when redundant cues are present, even people with a severe deficit for one type of cue can rely on another to improve their performance. This suggests that redundancy may be a design feature of music and language, one that assures transmission between people with diverse perceptual abilities.not peer-reviewed)

“…As mentioned, the acoustic speech signal carries multiple co-occurring acoustic dimensions (e.g. roughly described as pitch, duration, and amplitude), which often provide redundant cues to disambiguate a linguistic category (Patel, 2014;Winter, 2014;Jasmin et al, 2019a). Individuals with typical pitch perception have learned through a lifetime of experience with speech acoustics that vocal pitch is a useful and reliable cue.…”

Section: [H1] Introductionmentioning

confidence: 99%

Altered functional connectivity during speech perception in congenital amusia

Tierney

2019

Preprint

| Individuals with congenital amusia have a lifelong history of unreliable pitch processing. Accordingly, they downweight pitch cues during speech perception (even large, obvious ones), and instead rely on other dimensions like duration. We investigated the neural basis for this strategy. Using fMRI, individuals with amusia and controls (N=30) were scanned while they used pitch and duration cues to match auditory and visual sentences. A data-driven analysis procedure identified four 'seed' regions showing large Control > Amusic functional connectivity differences in lateral prefrontal cortex, which were examined with respect to the rest of the brain. Prominent decreases in functional connectivity were detected in the amusia group, between left prefrontal language-related regions (inferior and middle frontal gyrus/DLPFC) and right hemisphere pitch-related regions (auditory and anterior insular cortex). Our results suggest that individuals compensate for differences in the reliability of perceptual dimensions by regulating functional connectivity between taskrelevant frontal and perceptual regions. AMUSIA AND LANGUAGE PROCESSING