Biomedical subjects

Carol A Fowler

Publications and source records attributed to Carol A Fowler.

6 recordsLinked to original sources

PubMed2006

Visual influences on perception of speech and nonspeech vocal-tract events.

We report four experiments designed to determine whether visual information affects judgments of acoustically-specified nonspeech events as well as speech events (the "McGurk effect"). Previous findings have shown only weak McGurk effects for nonspeech stimuli, whereas strong effects are found for consonants. We used click sounds that serve as consonants in some African languages, but that are perceived as nonspeech by American English listeners. We found a significant McGurk effect for clicks presented in isolation that was much smaller than that found for stop-consonant-vowel syllables. In subsequent experiments, we found strong McGurk effects, comparable to those found for English syllables, for click-vowel syllables, and weak effects, comparable to those found for isolated clicks, for excised release bursts of stop consonants presented in isolation. We interpret these findings as evidence that the potential contributions of speech-specific processes on the McGurk effect are limited, and discuss the results in relation to current explanations for the McGurk effect.

Acoustic Stimulation↗

PubMed2006

Compensation for coarticulation reflects gesture perception, not spectral contrast.

This article reports three experiments designed to explore the basis for speech perceivers' apparent compensations for coarticulation. In the first experiment, the stimuli were members of three /da/-to-/ga/ continua hybridized from natural speech. The monosyllables had originally been produced in disyllables /ada/ and /aga/ to make Continuum 1, /alda/ and /alga/ (Continuum 2), and /arda/ and /arga/ (Continuum 3). Members of the second and third continua were influenced by carryover coarticulation from the preceding /l/ or /r/ context. Listeners showed compensation for this carryover coarticulation in the absence of the precursor /al/ or /ar/ syllables. This rules out an account in which compensation for coarticulation reflects a spectral contrast effect exerted by a precursor syllable, as previously has been proposed by Lotto, Holt, and colleagues (e.g., Lotto, Kluender, & Holt, 1997; Lotto & Kluender, 1998). The second experiment showed an enhancing effect of the endpoint monosyllables in Experiment 1 on identifications of preceding natural hybrids along an /al/-to-/ar/ continuum. That is, coarticulatory /l/ and /r/ information in /da/ and /ga/ syllables led to increased judgments of /l/ and /r/, respectively, in the precursor /al/-to-/ar/ continuum members. This was opposite to the effect, in Experiment 3, of /da/ and /ga/ syllables on preceding tones synthesized to range in frequency from approximately the ending F3 of /ar/ to the ending F3 of /al/. The enhancing, not contrastive, effect in Experiment 2, juxtaposed to the contrastive effect in Experiment 3, further disconfirms the spectral contrast account of compensation for coarticulation. A review of the literature buttresses that conclusion and provides strong support for an account that invokes listeners' attention to information in speech for the occurrence of gestural overlap.

Attention↗

PubMed2006

The motor theory of speech perception reviewed.

More than 50 years after the appearance of the motor theory of speech perception, it is timely to evaluate its three main claims that (1) speech processing is special, (2) perceiving speech is perceiving gestures, and (3) the motor system is recruited for perceiving speech. We argue that to the extent that it can be evaluated, the first claim is likely false. As for the second claim, we review findings that support it and argue that although each of these findings may be explained by alternative accounts, the claim provides a single coherent account. As for the third claim, we review findings in the literature that support it at different levels of generality and argue that the claim anticipated a theme that has become widespread in cognitive science.

Association Learning↗

PubMed2006

A sex difference in visual influence on heard speech.

Reports of sex differences in language processing are inconsistent and are thought to vary by task type and difficulty. In two experiments, we investigated a sex difference in visual influence onheard speech (the McGurk effect). First, incongruent consonant-vowel stimuli were presented where the visual portion of the signal was brief (100 msec) or full (temporally equivalent to the auditory). Second, to determine whether men and women differed in their ability to extract visual speech information from these brief stimuli, the same stimuli were presented to new participants with an additional visual-only (lipread) condition. In both experiments, women showed a significantly greater visual influence on heard speech than did men for the brief visual stimuli. No sex differences for the full stimuli or in the ability to lipread were found. These findings indicate that the more challenging brief visual stimuli elicit sex differences in the processing of audiovisual speech.

Adult↗

PubMed2004

Imitation in shadowing words.

Imitation of shadowed words was evaluated using Goldinger's (1998) AXB paradigm. The first experiment was a replication of Goldinger's experiments with different tokens. Experiment 1's AXB tests showed that shadowed words were judged to be better imitations of target words than were baseline (read) counterparts more often than chance (.50). Order of presentation of baseline and shadowed words in the AXB test also significantly influenced judgments. Degree of prior exposure to token words did not significantly influence judgments of imitation. Experiment 2 employed modified target tokens with extended voice onset times (VOTs). In addition to AXB tests, VOTs of response tokens were compared across baseline and shadowing conditions. The AXB tests revealed shadowed words to be better imitations of target tokens than baseline, without an influence of AXB presentation order. Differences between baseline and shadowing VOTs were greater when VOTs were extended. The implications of spontaneous imitation in nonsocial settings are considered.

Adult↗

PubMed2003

Mutual interpersonal postural constraints are involved in cooperative conversation.

The research was designed to evaluate interpersonal coordination during conversation with a new measurement tool. The experiment uses an analysis based on recurrence strategies, known as cross recurrence quantification, to evaluate the shared activity between 2 postural time series in reconstructed phase space. Pairs of participants were found to share more locations in phase space (greater recurrence) in conditions where they were conversing with one another to solve a puzzle task than in conditions in which they convened with others. The trajectories of pairs of participants also showed less divergence when they conversed with each other than when they conversed with others well. This is offered as objective evidence of interpersonal coordination of postural sway in the context of a cooperative verbal task.

Adult↗