Differences In Weighting Of Cues Research Articles

Individual Differences in Cue Weighting in Sentence Comprehension: An Evaluation Using Approximate Bayesian Computation.

Cue-based retrieval theories of sentence processing assume that syntactic dependencies are resolved through a content-addressable search process. An important recent claim is that in certain dependency types, the retrieval cues are weighted such that one cue dominates. This cue-weighting proposal aims to explain the observed average behavior, but here we show that there is systematic individual-level variation in cue weighting. Using the Lewis and Vasishth cue-based retrieval model, we estimated individual-level parameters for reading speed and cue weighting using 13 published datasets; hierarchical approximate Bayesian computation (ABC) was used to estimate the parameters. The modeling reveals a nuanced picture of cue weighting: we find support for the idea that some participants weight cues differentially, but not all participants do. Only fast readers tend to have the predicted higher weighting for structural cues, suggesting that reading proficiency (approximated here by reading speed) might be associated with cue weighting. A broader achievement of the work is to demonstrate how individual differences can be investigated in computational models of sentence processing without compromising the complexity of the model.

Pupillary entrainment reveals individual differences in cue weighting in 9-month-old German-learning infants

Young infants can segment continuous speech with statistical as well as prosodic cues. Understanding how these cues interact can be informative about how infants solve the segmentation problem. Here we investigate how German-speaking adults and 9-month-old German-learning infants weigh statistical and prosodic cues when segmenting continuous speech. We measured participants' pupil size while they were familiarized with a continuous speech stream where prosodic cues were pitted off against transitional probabilities. Adult participants' changes in pupil size synchronized with the occurrence of prosodic words during the familiarization and the temporal alignment of these pupillary changes was predictive of adult participants' performance at test. Further, 9-month-olds as a group failed to consistently segment the familiarization stream with prosodic or statistical cues. However, the variability in temporal alignment of the pupillary changes at word frequency showed that prosodic and statistical cues compete for dominance when segmenting continuous speech. A follow-up language development questionnaire at 40 months of age suggested that infants who entrained to prosodic words performed better on a vocabulary task and those infants who relied more on statistical cues performed better on grammatical tasks. Together these results suggest that statistics and prosody may serve different roles in speech segmentation in infancy.

Multilingualism and acoustic correlates of breathiness and tone in Kuy

Previous work on tonogenesis has focused primarily on intergenerational differences in cue weighting (Kang 2014, Coetzee et al. 2018) and less so on other sociolinguistic and language usage factors (though see Brunelle 2009). The current study explores the relationship of these variables with acoustic measures of voice quality (H1*-H2*, H1*-A1*, H1*-A2*, H1*-A3*, CPP, F1, f0) in a modal-breathy distinction in 63 speakers of Kuy, a minority language of Thailand. Kuy speakers are historically quadrilingual in Kuy, Thai, Lao, and Khmer, but recent centralization of Thailand has led to greater Thai usage. Because Thai is tonal and lacks a voice quality distinction, speakers who use Thai more are hypothesized to weigh f0 moreheavily and other breathiness measures less heavily. We find that f0 differences are significantly larger for speakers who use Thai more, while H1*-H2*, H1*-A1*, H1*-A2*, and H1*-A3* differences are slightly, but significantly, smaller. F1 shows no effect. Unexpectedly, CPP differences are also significantly larger for speakers who use Thai more. The results suggest that increasing Thai bilingualism plays a role in shifting voice quality cue weights and, in particular, in increasing f0 cue weights, providing one mechanism by which bilingualism in a tonal language may help catalyze tonogenesis.

Altered functional connectivity during speech perception in congenital amusia.

Individuals with congenital amusia have a lifelong history of unreliable pitch processing. Accordingly, they downweight pitch cues during speech perception and instead rely on other dimensions such as duration. We investigated the neural basis for this strategy. During fMRI, individuals with amusia (N = 15) and controls (N = 15) read sentences where a comma indicated a grammatical phrase boundary. They then heard two sentences spoken that differed only in pitch and/or duration cues and selected the best match for the written sentence. Prominent reductions in functional connectivity were detected in the amusia group between left prefrontal language-related regions and right hemisphere pitch-related regions, which reflected the between-group differences in cue weights in the same groups of listeners. Connectivity differences between these regions were not present during a control task. Our results indicate that the reliability of perceptual dimensions is linked with functional connectivity between frontal and perceptual regions and suggest a compensatory mechanism.

A longitudinal study of individual differences in the acquisition of new vowel contrasts

This study explores how individuals’ second language cue weighting strategies change over time and across different contrasts. The study investigates the developmental changes in perceptual cue weighting of two English vowel contrasts (/i/-/ɪ/ and /ɛ/-/æ/) by adult and child Korean learners of English during their first year of immersion in Canada. Longitudinal results revealed that adult learners had an initial advantage in L2 perceptual acquisition over children at least for the /i/-/ɪ/ contrast, but after one year some children showed greater improvements especially on the more difficult /ɛ/-/æ/ contrast. Both groups of Korean learners showed different acquisition patterns between the two vowel contrasts: they used both spectral and duration cues to distinguish /i/-/ɪ/ but generally only duration to distinguish /ɛ/-/æ/. By examining cue weights over time, this study partially confirmed the hypothesized developmental stages for the acquisition of L2 vowels first proposed by Escudero (2000) for Spanish learners of English. However, some unpredicted patterns were also identified. Most importantly, the longitudinal results suggest that individual differences in cue weighting are not merely random variability in the learner’s response patterns, but are systematically associated with the developmental trajectories of individual learners and those trajectories vary according to vowel contrast.

Individual differences in cue weights are correlated across contrasts

When listeners make judgments about phonological contrasts, they integrate different acoustic dimensions putting more weight on some than others. Individuals differ in how they weight different cues. Schultz, Francis & Llanos (2012) found that weights for VOT and f0 as cues to initial stop voicing in English are weakly positively correlated across individuals. We ask whether this is specific to VOT and f0 or a more general property of cue weighting across individuals. Secondly, across contrasts do the same listeners have stronger cue weights? 43 listeners performed a 2AFC task for four sets of minimal pairs that each varied orthogonally in two dimensions. All heard bet-bat and Luce-lose (vowel spectral quality vs. duration) and bog-dog (burst spectrum vs. formant transitions). 24 participants also heard sock-shock (sibilant spectrum vs. formant transitions) and the other 19 heard dear-tear (VOT vs. f0). Cue weights were fit with random slopes in a logistic regression for each minimal pair. Weights were positively correlated across individuals both within and across contrasts for bet-bat, Luce-lose, and sock-shock. Bog-dog and dear-tear had less consistent results. Overall this indicates that some individuals are better able to extract and use acoustic-phonetic information across different acoustic dimensions.

Diachronic change in perception of Korean sibilants

The laryngeal contrast in the Seoul dialect of Korean is in a state of flux: the increasing importance of f0 (relative to VOT) in both perception and production of the three-way stop contrast in younger (vs. older) Seoul speakers has been well-documented. The current work turns to perception of the Korean sibilant series, comprised of a three-way affricate contrast, (fortis vs. lenis vs. aspirated, parallel to the stop contrast) and a phonologically ambiguous two-way fricative contrast (fortis vs. “nonfortis”). We map younger (mean 33 years old) and older (mean 66) Seoul listeners’ perceptual spaces for the sibilant class using a five-way forced-choice task, with stimuli manipulated to vary independently across multiple acoustic dimensions (consonantal spectral information, vocalic spectral information, frication duration, aspiration duration, and f0). Hierarchical classification tree analyses reveal systematic age-related differences in cue-weighting. While both age groups make use of a combination of sp...

Perceptual weighting strategies of children with cochlear implants and normal hearing

PurposeThis study compared perceptual weighting strategies of children with cochlear implants (CIs) and children with normal hearing (NH), and asked if strategies are explained solely by degraded spectral representations, or if diminished language experience accounts for some of the effect. Relationships between weighting strategies and other language skills were examined. MethodOne hundred 8-year-olds (49 with NH and 51 with CIs) were tested on four measures: (1) labeling of cop–cob and sa–sha stimuli; (2) discrimination of the acoustic cues to the cop–cob decision; (3) phonemic awareness; and (4) word recognition. ResultsNo differences in weighting of cues to the cop–cob decision were observed between children with CIs and NH, suggesting that language experience was sufficient for the children with CIs. Differences in weighting of cues to the sa–sha decision were found, but were not entirely explained by auditory sensitivity. Weighting strategies were related to phonemic awareness and word recognition. ConclusionsMore salient cues facilitate stronger weighting of those cues. Nonetheless, individuals differ in how salient cues need to be to capture perceptual attention. Familiarity with stimuli also affects how reliably children attend to acoustic cues. Training should help children with CIs learn to categorize speech sounds with less-salient cues.Learning outcomes: After reading this article, the learner should be able to: (1) recognize methods and motivations for studying perceptual weighting strategies in speech perception; (2) explain how signal quality and language experience affect the development of weighting strategies for children with cochlear implants and children with normal hearing; and (3) summarize the importance of perceptual weighting strategies for other aspects of language functioning.

Individual differences in cue weights are stable across time: The case of Japanese stop lengths

Speech categories are defined by multiple acoustic dimensions, and listeners give differential weighting to dimensions in phonetic categorization. The informativeness (predictive strength) of dimensions for categorization is considered an important factor in determining perceptual weighting. However, it is unknown how the perceptual system weighs acoustic dimensions with similar informativeness. This study investigates perceptual weighting of two acoustic dimensions with similar informativeness, exploiting the absolute and relative durations that are nearly equivalent in signaling Japanese singleton and geminate stop categories. In the perception experiments, listeners showed strong individual differences in their perceptual weighting of absolute and relative durations. Furthermore, these individual patterns were stable over repeated testing across as long as 2 months and were resistant to perturbation through short-term manipulation of speech input. Listeners own speech productions were not predictive of how they weighted relative and absolute duration. Despite the theoretical advantage of relative (as opposed to absolute) duration cues across contexts, relative cues are not utilized by all listeners. Moreover, examination of individual differences in cue weighting is a useful tool in exposing the complex relationship between perceptual cue weighting and language regularities.

Do language-specific differences in primary acoustic cues affect relative weighting of secondary cues to phonological contrasts?

Cross-language differences in cue weighting are often attributed to differences in phonological inventories, in that listeners are assumed to give greater weight to those acoustic cues that best differentiate the specific phonological categories of their native language. However, subphonological properties of a given contrast may also affect weighting of acoustic cues for acoustic or perceptual reasons, in a manner independent of the structure of the listeners’ phonological inventory. Here, this possibility is investigated by comparing Spanish and English listeners’ relative weighting of two acoustic cues to the syllable-initial stop consonant voicing contrast /b/-/p/: Voice onset time (VOT) and fundamental frequency at the onset of voicing (onset f0). Spanish and English possess comparable word-initial stop consonant inventories, but differ in the phonetic realization of the voicing contrast in terms of VOT: Spanish contrasts a short lag (<10 ms) /p/ with a prevoiced (<0 ms) /b/, while English contrasts a long lag (> 50 ms) /p/ with a short lag (<20 ms) /b/. Preliminary results (N = 7) suggest that, although speakers from both languages depend mainly on VOT, Spanish speakers give more weight to onset f0 when VOT is ambiguous than do English listeners.

Individual variability in cue-weighting and lexical tone learning

Speech sound patterns can be discerned using multiple acoustic cues. The relative weighting of these cues is known to be language-specific. Speech-sound training in adults induces changes in cue-weighting such that relevant acoustic cues are emphasized. In the current study, the extent to which individual variability in cue weighting contributes to differential success in learning to use foreign sound patterns was examined. Sixteen English-speaking adult participants underwent a sound-to-meaning training paradigm, during which they learned to incorporate Mandarin linguistic pitch contours into words. In addition to cognitive tests, measures of pitch pattern discrimination and identification were collected from all participants. Reaction time data from the discrimination task was subjected to 3-way multidimensional scaling to extract dimensions underlying tone perception. Two dimensions relating to pitch height and pitch direction were found to underlie non-native tone space. Good learners attended more to pitch direction relative to poor learners, before and after training. Training increased the ability to identify and label pitch direction. The results demonstrate that variability in the ability to successfully learn to use pitch in lexical contexts can be explained by pre-training differences in cue-weighting.

Age-related differences in weighting and masking of two cues to word-final stop voicing in noise

Because laboratory studies are conducted in optimal listening conditions, often with highly stylized stimuli that attenuate or eliminate some naturally occurring cues, results may have constrained applicability to the "real world." Such studies show that English-speaking adults weight vocalic duration greatly and formant offsets slightly in voicing decisions for word-final obstruents. Using more natural stimuli, Nittrouer [J. Acoust. Soc. Am. 115, 1777-1790 (2004)] found different results, raising questions about what would happen if experimental conditions were even more like the real world. In this study noise was used to simulate the real world. Edited natural words with voiced and voiceless final stops were presented in quiet and noise to adults and children (4 to 8 years) for labeling. Hypotheses tested were (1) Adults (and perhaps older children) would weight vocalic duration more in noise than in quiet; (2) Previously reported age-related differences in cue weighting might not be found in this real-world simulation; and (3) Children would experience greater masking than adults. Results showed: (1) no increase for any age listeners in the weighting of vocalic duration in noise; (2) age-related differences in the weighting of cues in both quiet and noise; and (3) masking effects for all listeners, but more so for children than adults.

Do humans optimally integrate stereo and texture information for judgments of surface slant?

An optimal linear system for integrating visual cues to 3D surface geometry weights cues in inverse proportion to their uncertainty. The problem of integrating texture and stereo information for judgments of planar surface slant provides a strong test of optimality in human perception. Since the accuracy of slant from texture judgments changes by an order of magnitude from low to high slants, optimality predicts corresponding changes in cue weights as a function of surface slant. Furthermore, since humans show significant individual differences in their abilities to use both texture and stereo information for judgments of 3D surface geometry, the problem admits the stronger test that individual differences in subjects’ thresholds for discriminating slant from the individual cues should predict individual differences in cue weights. We tested both predictions by measuring slant discrimination thresholds and stereo/texture cue weights as a function of surface slant for multiple subjects. The results bear out both predictions of optimality, with the exception of an apparent slight under-weighting of texture information. This may be accounted for by factors specific to the stimuli used to isolate stereo information in the experiments. Taken together, the results are consistent with the hypothesis that humans optimally combine the two cues to surface slant, with cue weights proportional to the subjective reliability of the cues.