Biomedical subjects

Sven L Mattys

Publications and source records attributed to Sven L Mattys.

5 recordsLinked to original sources

PubMed2005

Integration of multiple speech segmentation cues: a hierarchical framework.

A central question in psycholinguistic research is how listeners isolate words from connected speech despite the paucity of clear word-boundary cues in the signal. A large body of empirical evidence indicates that word segmentation is promoted by both lexical (knowledge-derived) and sublexical (signal-derived) cues. However, an account of how these cues operate in combination or in conflict is lacking. The present study fills this gap by assessing speech segmentation when cues are systematically pitted against each other. The results demonstrate that listeners do not assign the same power to all segmentation cues; rather, cues are hierarchically integrated, with descending weights allocated to lexical, segmental, and prosodic cues. Lower level cues drive segmentation when the interpretive conditions are altered by a lack of contextual and lexical information or by white noise. Taken together, the results call for an integrated, hierarchical, and signal-contingent approach to speech segmentation.

Cues↗

PubMed2005

Detecting silent pauses in speech: a new tool for measuring on-line lexical and semantic processing.

In this study, we introduce pause detection (PD) as a new tool for studying the on-line integration of lexical and semantic information during speech comprehension. When listeners were asked to detect 200-ms pauses inserted into the last words of spoken sentences, their detection latencies were influenced by the lexical-semantic information provided by the sentences. Listeners took longer to detect a pause when it was inserted within a word that had multiple potential endings, rather than a unique ending, in the context of the sentence. An event-related potential (ERP) variant of the PD procedure revealed brain correlates of pauses as early as 101 to 125 ms following pause onset and patterns of lexical-semantic integration that mirrored those obtained with PD within 160 ms of pause onset. Thus, both the behavioral and the electrophysiological responses to pauses suggest that lexical and semantic processes are highly interactive and that their integration occurs rapidly during speech comprehension.

Humans↗

PubMed2005

How do syllables contribute to the perception of spoken English? insight from the migration paradigm.

The involvement of syllables in the perception of spoken English has traditionally been regarded as minimal because of ambiguous syllable boundaries and overriding rhythmic segmentation cues. The present experiments test the perceptual separability of syllables and vowels in spoken English using the migration paradigm. Experiments 1 and 2 show that syllables migrate considerably more than full and reduced vowels, and this effect is not influenced by the lexicality of the stimuli, their stress pattern, or the syllables' position relative to the edge of the stimuli. Experiment 3 confirms the predominance of syllable migration against a pseudosyllable baseline, and provides some evidence that syllable migration depends on whether syllable boundaries are clear or ambiguous. Consistent with this hypothesis, Experiment 4 demonstrates that CVC syllables migrate more in stimuli with a clear CVC-initial structure than in ambisyllabic stimuli. Together, the data suggest that syllables have a greater contribution to the perception of spoken English than previously assumed.

Analysis of Variance↗

PubMed2004

Stress versus coarticulation: toward an integrated approach to explicit speech segmentation.

Although word stress has been hailed as a powerful speech-segmentation cue, the results of 5 cross-modal fragment priming experiments revealed limitations to stress-based segmentation. Specifically, the stress pattern of auditory primes failed to have any effect on the lexical decision latencies to related visual targets. A determining factor was whether the onset of the prime was coarticulated with the preceding speech fragment. Uncoarticulated (i.e., concatenated) primes facilitated priming. Coarticulated ones did not. However, when the primes were presented in a background of noise, the pattern of results reversed, and a strong stress effect emerged: Stress-initial primes caused more pruning than non-initial-stress primes, regardless of the coarticulatory cues. The results underscore the role of coarticulation in the segmentation of clear speech and that of stress in impoverished listening conditions. More generally, they call for an integrated and signal-contingent approach to speech segmentation.

Cues↗

PubMed2002

Stimulus-based lexical distinctiveness as a general word-recognition mechanism.

Word recognition is generally assumed to be achieved via competition in the mental lexicon between phonetically similar word forms. However, this process has so far been examined only in the context of auditory phonetic similarity. In the present study, we investigated whether the influence of word-form similarity on word recognition holds in the visual modality and with the patterns of visual phonetic similarity. Deaf and hearing participants identified isolated spoken words presented visually on a video monitor. On the basis of computational modeling of the lexicon from visual confusion matrices of visual speech syllables, words were chosen to vary in visual phonetic distinctiveness, ranging from visually unambiguous (lexical equivalence class [LEC] size of 1) to highly confusable (LEC size greater than 10). Identification accuracy was found to be highly related to the word LEC size and frequency of occurrence in English. Deaf and hearing participants did not differ in their sensitivity to word LEC size and frequency. The results indicate that visual spoken word recognition shows strong similarities with its auditory counterpart in that the same dependencies on lexical similarity and word frequency are found to influence visual speech recognition accuracy. In particular, the results suggest that stimulus-based lexical distinctiveness is a valid construct to describe the underlying machinery of both visual and auditory spoken word recognition.

Adult↗