Biomedical subjects

J W Mullennix

Publications and source records attributed to J W Mullennix.

7 recordsLinked to original sources

PubMed1992

Automaticity and the detection of speech.

The development of automatic perceptual responses to speech stimuli was examined. In the first experiment, phoneme-monitoring performance for speech syllables was examined under conditions in which stimulus-to-response mapping and memory load were manipulated. The results indicated that automaticity develops under consistent-mapping conditions. In the second experiment, a dual-task procedure was combined with mapping and selective attention manipulations in order to examine the development of automaticity across single- and multiple-channel conditions. The results indicated that performance under consistently mapped training conditions was interfered with by dividing attention across multiple channels of input. It is concluded that there may be differences in the way that automaticity develops across visual and auditory modalities and that these differences need to be examined more closely.

Attention↗

PubMed1991

Comprehension of synthetic speech produced by rule: word monitoring and sentence-by-sentence listening times.

Previous comprehension studies using postperceptual memory tests have often reported negligible differences in performance between natural speech and several kinds of synthetic speech produced by rule, despite large differences in segmental intelligibility. The present experiments investigated the comprehension of natural and synthetic speech using two different on-line tasks: word monitoring and sentence-by-sentence listening. On-line task performance was slower and less accurate for passages of synthetic speech than for passages of natural speech. Recognition memory performance in both experiments was less accurate following passages of synthetic speech than of natural speech. Monitoring performance, sentence listening times, and recognition memory accuracy all showed moderate correlations with intelligibility scores obtained using the Modified Rhyme Test. The results suggest that poorer comprehension of passages of synthetic speech is attributable in part to the greater encoding demands of synthetic speech. In contrast to earlier studies, the present results demonstrate that on-line tasks can be used to measure differences in comprehension performance between natural and synthetic speech.

Adult↗

PubMed1990

Stimulus variability and processing dependencies in speech perception.

Processing dependencies in speech perception between voice and phoneme were investigated using the Garner (1974) speeded classification procedure. Variability in the voice of the talker and in the cues to word-initial consonants were manipulated. The results showed that the processing of a talker's voice and the perception of voicing are asymmetrically dependent. In addition, when stimulus variability was increased in each dimension, the amount of orthogonal interference obtained for each dimension became significantly larger. The processing asymmetry between voice and phoneme was interpreted in terms of a parallel-contingent relationship of talker normalization processes to auditory-to-phonetic coding processes. The processing of voice information appears to be qualitatively different from the encoding of segmental phonetic information, although they are not independent. Implications of these results for current theories of speech perception are discussed.

Adult↗

PubMed1989

Effects of talker variability on recall of spoken word lists.

Three experiments were conducted to investigate recall of lists of words containing items spoken by either a single talker or by different talkers. In each experiment, recall of early list items was better for lists spoken by a single talker than for lists of the same words spoken by different talkers. The use of a memory preload procedure demonstrated that recall of visually presented preload digits was superior when the words in a subsequent list were spoken by a single talker than by different talkers. In addition, a retroactive interference task demonstrated that the effects of talker variability on the recall of early list items were not due to use of talker-specific acoustic cues in working memory at the time of recall. Taken together, the results suggest that word lists produced by different talkers require more processing resources in working memory than do lists produced by a single talker. The findings are discussed in terms of the role that active rehearsal plays in the transfer of spoken items into long-term memory and the factors that may affect the efficiency of rehearsal.

Adult↗

PubMed1989

Some effects of talker variability on spoken word recognition.

The perceptual consequences of trial-to-trial changes in the voice of the talker on spoken word recognition were examined. The results from a series of experiments using perceptual identification and naming tasks demonstrated that perceptual performance decreases when the voice of the talker changes from trial to trial compared to performance when the voice on each trial remains the same. In addition, the effects of talker variability on word recognition appeared to be more robust and less dependent on task than the effects of word frequency and lexical structure. Possible hypotheses regarding the nature of the processes giving rise to these effects are discussed, with particular attention to the idea that the processing of information about the talker's voice is intimately related to early perceptual processes that extract acoustic-phonetic information from the speech signal.

Adult↗

PubMed1987

Integral processing of phonemes: evidence for a phonetic mode of perception.

To investigate the extent and locus of integral processing in speech perception, a speeded classification task was utilized with a set of noise-tone analogs of the fricative-vowel syllables (fae), (integral of ae), (fu), and (integral of u). Unlike the stimuli used in previous studies of selective perception of syllables, these stimuli did not contain consonant-vowel transitions. Subjects were asked to classify on the basis of one of the two syllable components. Some subjects were told that the stimuli were computer generated noise-tone sequences. These subjects processed the noise and tone separably. Irrelevant variation of the noise did not affect reaction times (RTs) for the classification of the tone, and vice versa. Other subjects were instructed to treat the stimuli as speech. For these subjects, irrelevant variation of the fricative increased RTs for the classification of the vowel, and vice versa. A second experiment employed naturally spoken fricative-vowel syllables with the same task. Classification RTs showed a pattern of integrality in that irrelevant variation of either component increased RTs to the other. These results indicate that knowledge of coarticulation (or its acoustic consequences) is a basic element of speech perception. Furthermore, the use of this knowledge in phonetic coding is mandatory, even in situations where the stimuli do not contain coarticulatory information.

Adult↗

PubMed1985

When selective adaptation and contrast effects are distinct: a reply to Diehl, Kluender, and Parker.

Two alternative conceptualizations of selective adaptation with speech have recently received attention. The adaptation level theory (AL) outlined by Diehl (1981) and a two-stage model outlined by Sawusch and Jusczyk (1981) can both account for much of the adaptation and paired-comparison data. Recently, Diehl, Kluender, and Parker (1985) proposed that all adaptation and contrast data can be accounted for by AL theory. They reported the results of a study that showed evidence of streaming in selective adaptation and claimed that their results provide a counterdemonstration to recent studies that have argued against the AL approach. In the present article, an outline of how the Diehl et al. results can be accounted for by both the two-stage model and AL theory is presented. In addition, a new set of results comparing adaptation and paired-comparison procedures is presented. These results are precisely as predicted by the two-stage model, but they can not be handled by AL theory.

Adaptation, Physiological↗