Carol A. Fowler

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.

Functionally specific articulatory cooperation following jaw perturbations during speech: Evidence for coordinative structures.

In three experiments we show that articulatory patterns in response to jaw perturbations are specific to the utterance produced. In Experiments 1 and 2, an unexpected constant force load (5.88 N) applied during upward jaw motion for final /b/ closure in the utterance /baeb/ revealed nearly immediate compensation in upper and lower lips, but not the tongue, on the first perturbation trial. The same perturbation applied during the utterance /baez/ evoked rapid and increased tongue-muscle activity for /z/ frication, but no active lip compensation. Although jaw perturbation represented a threat to both utterances, no perceptible distortion of speech occurred. In Experiment 3, the phase of the jaw perturbation was varied during the production of bilabial consonants. Remote reactions in the upper lip were observed only when the jaw was perturbed during the closing phase of motion. These findings provide evidence for flexibly assembled coordinative structures in speech production.

Relations among regular and irregular morphologically related words in the lexicon as revealed by repetition priming.

Several experiments examined repetition priming among morphologically related words as a tool to study lexical organization. The first experiment replicated a finding by Stanners, Neiser, Hernon, and Hall (Journal of Verbal Learning and Verbal Behavior, 1979,18, 399-412), that whereas inflected words prime their unaffixed morphological relatives as effectively as do the unaffixed forms themselves, derived words are effective, but weaker, primes. The experiment also suggested, however, that this difference in priming may have an episodic origin relating to the less formal similarity of derived than of inflected words to unaffixed morphological relatives. A second experiment reduced episodic contributions to priming and found equally effective priming of unaffixed words by themselves, by inflected relatives, and by derived relatives. Two additional experiments found strong priming among relatives sharing the spelling and pronunciation of the unaffixed stem morpheme, sharing spelling alone, or sharing neither formal property exactly. Overall, results with auditory and visual presentations were similar. Interpretations that repetition priming reflects either repeated access to a common lexical entry or associative semantic priming are both rejected in favor of a lexical organization in which components of a word (e.g., a stem morpheme) may be shared among distinct words without the words themselves, in any sense, sharing a “lexical entry.”

Coordination and Coarticulation in Speech Production

In this article, we consider the concepts of coordination and coarticulation in speech production in the context of a task-dynamic model. Coordination reflects the transient establishment of constrained relationships among articulators that jointly produce linguistically significant actions of the vocal tract – that is phonetic gestures – in a flexible, context-sensitive manner. We ascribe the need for these constraints in part to the requirement of coarticulatory overlap in speech production. Coarticulation reflects temporally staggered activation of coordinative constraints for different phonetic gestures. We suggest that the anticipatory coarticulatory field for a gesture is more limited than look-ahead models have suggested, consistent with the idea that anticipatory coarticulation is the onset of activation of coordinative constraints for a forthcoming gesture. Finally, we ascribe much of the context-sensitivity in the anticipatory or carryover fields of a gesture (variation due to “coarticulation resistance”) to low-level (below the speech plan) interactions among the coordinative constraints for temporally overlapping gestures.

Converging sources of evidence on spoken and perceived rhythms of speech: cyclic production of vowels in monosyllabic stress feet.

The article reviews the literature from psychology, phonetics, and phonology bearing on production and perception of syllable timing in speech. A review of the psychological and phonetics literature suggests that production of vowels and consonants are interleaved in syllable sequences in such a way that vowel production is continuous or nearly so. Based on that literature, a hypothesis is developed concerning the perception of syllable timing assuming that vowel production is continuous. The hypothesis is that perceived syllable timing corresponds to the times sequencing of the vowels as produced and not to the timing either of vowel onsets as conventionally measured or of syllable-initial consonants. Three experiments support the hypothesis. One shows that information present during the portion of an acoustic signal in which a syllable-initial consonant predominates is used by listeners to identify the vowel. Compatibly, this information for the vowel contributes to the vowels perceived duration. Finally, a measure of the perceived timing of a syllable correlates significantly with the time required to identify syllable-medial vowels but not with time to identify the syllable-initial consonants. Further support for the proposed mode of vowel-consonant production and perception is derived from the literature on phonology. Language-specific phonological conventions can be identified that may reflect exaggerations and conventionalizations of the articulatory tendency for vowels to be produced continuously in speech.

Segmentation of coarticulated speech in perception

The research investigates how listeners segment the acoustic speech signal into phonetic segments and explores implications that the segmentation strategy may have for their perception of the (apparently) context-sensitive allophones of a phoneme. Two manners of segmentation are contrasted. In one, listeners segment the signal into temporally discrete, context-sensitive segments. In the other, which may be consistent with the talker’s production of the segments, they partition the signal into separate, but overlapping, segments freed of their contextual influences. Two complementary predictions of the second hypothesis are tested. First, listeners will use anticipatory coarticulatory information for a segment as information for the forthcoming segment. Second, subjects will not hear anticipatory coarticulatory information as part of the phonetic segment with which it co-occurs in time. The first hypothesis is supported by findings on a choice reaction time procedure; the second is supported by findings on a 4IAX discrimination test. Implications of the findings for theories of speech production, perception, and of the relation between the two are considered.

Phonetic recoding and reading difficulty in beginning readers.

The results of a recent study (Liberman, Shankweiler, Liberman, Fowler, & Fischer, 1977) suggest that good beginning readers are more affected than poor readers by the phonetic characteristics of visually presented items in a recall task. The good readers made significantly more recall errors on strings of letters with rhyming letter names than on nonrhyming sequences; in contrast, the poor readers made roughly equal numbers of errors on the rhyming and nonrhyming letter strings. The purpose of the present study was to determine whether the interaction between reading ability and phonetic similarity is solely determined by different rehearsal strategies of the two groups. Accordingly, good and poor readers were tested on rhyming and nonrhyming words using a recognition memory paradigm that minimized the opportunity for rehearsal. Performance of the good readers was more affected by phonetic similarity than that of the poor readers, in agreement with the earlier study. The present findings support the hypothesis that good and poor readers do differ in their ability to access a phonetic representation.

Fundamental frequency declination is not unique to human speech: Evidence from nonhuman primates

In human speech, declination of the fundamental frequency (F0) of the voice spans coherent units of an utterance and, therefore, signals where units begin and end. A rapid final fall at the end of an utterance provides a further indication of an utterance’s ending. The occurrence of declination is sufficiently widespread across languages that several investigators have suggested it as a language universal. Language universals may be universal because they are part of a species‐specific specialization for language or, alternatively, they may constitute conventionalizations of natural dispositions of the vocal tract that may serve a communicative function. Evidence is offered favoring the latter account for declination and the final fall by showing that vocal productions of vervet monkeys (Cercopithecus aethiops) and rhesus macaques (Macaca mulatta) show declination, and vervets show clear evidence of a final fall. Interestingly, the fall in F0 may serve some communicative role in the vocal exchanges of ver...

Formal relationships among words and the organization of the mental lexicon

A series of experiments investigated the role of orthography in the organization of the mental lexicon. A pilot experiment had found no effect of formal overlap between words on a repetition priming task at a lag of 56 intervening items. The first two experiments reported here used a lag of zero and varied SOA. Formal priming was found at SOAs of 1,650 milliseconds and less. However, reducing the proportion of related primes and targets in the experiment reduced formal priming. Moreover, it did so not by affecting response times to formally related primes and targets but by reducing response times to comparison trials in which primes and targets were unrelated. This led to a hypothesis that the formal priming we had observed was only apparent and due to strategic inhibition of responses to unrelated prime-target pairs. The final experiment reduced the proportion of responses to related targets further and examined formal priming at lags of 0, 1, 3, and 10. No formal priming was found under these conditions. Across all experiments, where formal priming occurred, it was due to changes in levels of inhibitory priming in comparison conditions. The conclusion is drawn that convincing evidence for an orthographic or phonological organization of the lexicon is not obtainable using priming procedures.

Coarticulation resistance of American English consonants and its effects on transconsonantal vowel-to-vowel coarticulation

We explored the variation in the resistance that lingual and non lingual consonants exhibit to coarticulation by following vowels in the schwa+CV disyllables of two native speakers of English. Generally, lingual consonants other than /g/ were more resistant tho coarticulation than thhe liabial consonants /b/ and /v/. Coarticulation resistance in the consonant also affected articulatory evidence for trans consonantal vowel-to-vowel coarticulation, but did not show consistent acoustic effects. As for effects of coarticulation resistance in thhe following vowel, articulatory and acoustic effects were quite liarge at consonantre lease but much weaker farther into the following stressed vowel. Correlations between coarticulation resistance effects at consonantrelease and liocus equation slopes were highly significant, consistent with the view that variation in coarticulation resistance explains differences among consonants in liocus equation slopes.