Speech perception as categorization

Speech perception (SP) most commonly refers to the perceptual mapping from the highly variable acoustic speech signal to a linguistic representation, whether it be phonemes, diphones, syllables, or words. This is an example of categorization, in that potentially discriminable speech sounds are assigned to functionally equivalent classes. In this tutorial, we present some of the main challenges to our understanding of the categorization of speech sounds and the conceptualization of SP that has resulted from these challenges. We focus here on issues and experiments that define open research questions relevant to phoneme categorization, arguing that SP is best understood as perceptual categorization, a position that places SP in direct contact with research from other areas of perception and cognition.     

Effects of Attention on the Strength of Lexical Influences on Speech Perception: Behavioral Experiments and Computational Mechanisms

The effects of lexical context on phonological processing are pervasive and there have been indications that such effects may be modulated by attention. However, attentional modulation in speech processing is neither well documented nor well understood. Experiment 1 demonstrated attentional modulation of lexical facilitation of speech sound recognition when task and critical stimuli were identical across attention conditions. We propose modulation of lexical activation as a neurophysiologically plausible computational mechanism that can account for this type of modulation. Contrary to the claims of critics, this mechanism can account for attentional modulation without violating the principle of interactive processing. Simulations of the interactive TRACE model extended to include two different ways of modulating lexical activation showed that each can account for attentional modulation of lexical feedback effects. Experiment 2 tested conflicting predictions from the two implementations and provided evidence that is consistent with bias input as the mechanism of attentional control of lexical activation.     

Setting limits on children's behavior: The differential effects of controlling vs. informational styles on intrinsic motivation and creativity

The imposition of external constraints on an activity has frequently been shown to undermine intrinsic motivation. Given that limits must often be set upon peoples' activities, especially in parenting and education, the present study addressed the question of whether limits can be set without undermining intrinsic motivation for the activity being limited. Using cognitive evaluation theory, contrasting limit setting styles of either a controlling or informational nature, or no limits, were placed upon forty-four first- and second-grade children engaged in a painting activity. The intrinsic motivation, enjoyment, creativity, and quality of artistic production were expected to be decreased by controlling limits relative to informational and no-limits, which were not expected to differ from each other. The results provided substantial support for these predictions, suggesting that limits can be set without undermining intrinsic motivation if they are informational in nature. Support was also found for the consensual assessment of creativity method recently developed by Amabile (1982a). Results of the study are discussed along with the general relation between creativity and intrinsic motivation.     

Teaching gender-related material: The effect of group sex composition on perceptions of a female instructor

This study investigated how group sex composition affects female and male students' perceptions of female instructors who teach in the area of counseling women. Three components of person perception were assessed: cognitive, affective, and behavioral. The cognitive domain included evaluations of the instructor and the subject matter presented; the affective domain included emotional responses to the instructor and the subject matter; and the behavioral domain included actions in response to the instructor, operationalized as the number of questions asked by students. Students with some interest in a career in the helping professions viewed one of two videotapes either with a group of same-sex peers or in a group in which they were the only male or female. One tape described a gender-neutral topic (psychology and the law) and the other described a female gender-related topic (sex bias in counseling women). The same female instructor made both presentations. Students then completed the measures. As predicted, the sex composition of the student group affected person perception, especially in the affective and behavior domains. Recommendations are made for future research.This study was supported by a small grant from the University Research Institute, University of Texas at Austin. Appreciation is expressed to Sherry Fowler, Bob Haverstick, and Kathy Thomas for help with data collection and to Carolyn Bates and Ken Wilgus for coding the open-ended responses. A paper based on this research was presented at the meetings of the American Psychological Association, August 1987.     

A Longitudinal Study of Religiosity,Spiritual Health Locus of Control,and Health Behaviors in a National Sample of African Americans

The present longitudinal study examined religious beliefs and behaviors, spiritual health locus of control (SHLOC), and selected health-related behaviors and outcomes in a national sample of 766 African American adults. Participants were interviewed by telephone three times over a 5-year period. Results indicated that stronger religious beliefs and religious behaviors were associated with greater changes in active SHLOC. There was some evidence of direct effects of religious beliefs and behaviors on changes in health behaviors. Religious behaviors were related to greater passive SHLOC over time across some health outcomes. Passive SHLOC was associated with some less desirable health outcomes over time.     

Are there interactive processes in speech perception?

Lexical information facilitates speech perception, especially when sounds are ambiguous or degraded. The interactive approach to understanding this effect posits that this facilitation is accomplished through bi-directional flow of information, allowing lexical knowledge to influence pre-lexical processes. Alternative autonomous theories posit feed-forward processing with lexical influence restricted to post-perceptual decision processes. We review evidence supporting the prediction of interactive models that lexical influences can affect pre-lexical mechanisms, triggering compensation, adaptation and retuning of phonological processes generally taken to be pre-lexical. We argue that these and other findings point to interactive processing as a fundamental principle for perception of speech and other modalities.     

More on the fragility of performance: choking under pressure in mathematical problem solving

In 3 experiments, the authors examined mathematical problem solving performance under pressure. In Experiment 1, pressure harmed performance on only unpracticed problems with heavy working memory demands. In Experiment 2, such high-demand problems were practiced until their answers were directly retrieved from memory. This eliminated choking under pressure. Experiment 3 dissociated practice on particular problems from practice on the solution algorithm by imposing a high-pressure test on problems practiced 1, 2, or 50 times each. Infrequently practiced high-demand problems were still performed poorly under pressure, whereas problems practiced 50 times each were not. These findings support distraction theories of choking in math, which contrasts with considerable evidence for explicit monitoring theories of choking in sensorimotor skills. This contrast suggests a skill taxonomy based on real-time control structures.