Insights from a failure of selective adaptation: syllable-initial and syllable-final consonants are different

Selective adaptation with a syllable-initial consonant fails to affect perception of the same consonant in syllable-final position, and vice versa. One account of this well-replicated result invokes a cancellation explanation: with the place-of-articulation stimuli used, the pattern of formant transitions switches according to syllabic position, allowing putative phonetic-level effects to be opposed by putative acoustic-level effects. Three experiments tested the cancellation hypothesis by preempting the possibility of acoustic countereffects. In Experiment 1, the test syllables and adaptors were /r/-/l/CVs and VCs, which do not produce cancelling formant patterns across syllabic position. In Experiment 2, /b/-/d/ continua were used in a paired-contrast procedure, believed to be sensitive to phonetic, but not acoustic, identity. In Experiment 3, cross-ear adaptation, also believed to tap phonetic rather than acoustic processes, was used. All three experiments refuted the cancellation hypothesis. Instead, it appears that the perceptual process treats syllable-initial consonants and syllable-final ones as inherently different. These results provide support for the use of demisyllabic representations in speech perception.     

Phonetic prototypes

Speech perception may be viewed as a phonetic categorization task in which the listener assigns incoming sounds to various phonetic categories. The present experiment tests two classes of models of phonetic categorization: (1) models in which the listener has a threshold or boundary between alternative categories vs. (2) models in which the listener compares the input to prototypical representations of the alternative phones. In a pretest, listeners located on a VOT continuum the /ga/ that they thought was prototypical. Selective adaptation was then conducted using both the selected prototype and adaptors nearer and further from the phoneme boundary. The prototype adaptor produced more adaptation than the other adaptors. This result supports a prototype-based representation for phonetic categorization; several process models using such a representation are considered.     

Logical relations and comprehension in conversation

This study examines how logical relations (e.g., causality and identity) in spoken discourse affect comprehension. Research on cohesion, which shows that specific unit template structures link discourse and text together, is used to build a model of language comprehension that places template structures at the base of a context comparison operation. Subjects were engaged in ordinary conversation with a confederate trained to produce specific types of logical utterances unobtrusively. The comprehension model predicted that systematically different latencies, topical response, and remedial response of subjects would follow the test items produced by the confederate. The data support the predictions. It is shown that comprehension occurs via one processing path if there is a direct tie between the target item and the immediately prior item in discourse, and a separate processing path if the tie is between the target item and the earlier context. Subject response in conversation is shown to display useful evidence on the nature of comprehension achieved. The findings specify and extend the recent research on the integration of new information into a textual structure.     

Initial response to rape: The impact of factors within the rape situation

The relationship between specific aspects of the rape situation and immediate post-rape measures of depression, fear, anxiety, and social and interpersonal functioning in 50 recent victims of sexual assault was examined. The data failed to reveal any significant relationships between rape situation variables (e.g., stranger vs. known assailant, weapon vs. no weapon) and the nature or severity of the victims' psychological response. It is emphasized that this negative finding contradicts previous and current clinical lore, and has a number of implications for the assessment and treatment of rape victims.This research was supported by a grant from the National Institute of Mental Health (MH#29692) to the first two authors.     

Syntactic locus as a determinant of judged pause duration

This study sought to determine if the syntactic location of a speech pause might affect its apparent duration. Ss listened to a continuous discourse, being required to attend to its content as well as to make judgments, now and then, as to the duration of particular pauses. For pauses all actually of the same length, it was found that those falling at a minor within-sentence break, as syntactically defined, were characteristically judged to be longer than those falling at a major within-sentence break or at a between-sentence break, with no difference between the two latter cases. These results, obtained in a perceptual task involving a minimum of extraordinary or disruptive features, are taken as evidence for the power of syntactic variables in affecting attention during listening to speech.