Effect of Music Training on Categorical Perception of Speech and Music

Background and Objectives: The aim of this study is to evaluate the effect of music training on the characteristics of auditory perception of speech and music. The perception of speech and music stimuli was assessed across their respective stimulus continuum and the resultant plots were compared between musicians and non-musicians. Subjects and Methods: Thirty musicians with formal music training and twenty-seven non-musicians participated in the study (age: 20 to 30 years). They were assessed for identification of consonant-vowel syllables (/da/ to /ga/), vowels (/u/ to /a/), vocal music note (/ri/ to /ga/), and instrumental music note (/ri/ to /ga/) across their respective stimulus continuum. The continua contained 15 tokens with equal step size between any adjacent tokens. The resultant identification scores were plotted against each token and were analyzed for presence of categorical boundary. If the categorical boundary was found, the plots were analyzed by six parameters of categorical perception; for the point of 50% crossover, lower edge of categorical boundary, upper edge of categorical boundary, phoneme boundary width, slope, and intercepts. Results: Overall, the results showed that both speech and music are perceived differently in musicians and non-musicians. In musicians, both speech and music are categorically perceived, while in non-musicians, only speech is perceived categorically. Conclusions: The findings of the present study indicate that music is perceived categorically by musicians, even if the stimulus is devoid of vocal tract features. The findings support that the categorical perception is strongly influenced by training and results are discussed in light of notions of motor theory of speech perception.

Voice Morphing

Voice morphing is a framework to generate a new sound which has the mixed attribute of given voice examples. It provides a flexible tool for investigating perceptual attributes in voice communication, especially for quantifying paralinguistic and extralinguistic cues. Recent advances in parametric representation of speech sounds have made the morphing-based approach a practical alternative or complementary strategy to procedures using speech-production models. Stimulus continuum spanning between two typical voice recordings having different perceptual attributes provides an external reference to quantify subjective responses. Generalized morphing, which enables extrapolation as well as interpolation of arbitrarily many numbers of voices, provides a unique strategy for investigating speaker identity. Its ability to selectively manipulate any combination of fundamental parameters facilitates the development of technology to intervene and mediate paralinguistic and extralinguistic communication channels.

Decisional Processing in Paranoid and Non-Paranoid Schizophrenics

40 schizophrenic subjects, divided into paranoid/non-paranoid categories and 14 normal controls were presented a task which involved making “same-different” judgments during random presentations of a series of visual comparison stimuli with a standard which represented the midpoint of the stimulus continuum. Using Sternberg's Choice RT paradigm for studying the locus of cognitive deficit, difficulty at the response-selection stage was manipulated while holding other stages constant. It was predicted that paranoids would have shorter RTs at easy decision points and longer RTs at difficult decision points relative to non-paranoids. The directions of the differences were as predicted but did not attain statistical significance. Both schizophrenic groups, compared to normals, made significantly fewer “same” responses on those trials where the comparison and standard were most similar.

Continuous Repertoire: Multiple-Response Control by a Continuous Stimulus Dimension

Three points of correspondence were trained between a continuous stimulus dimension and a quasi-continuous response dimension. Human subjects were then tested with novel test stimuli from the stimulus continuum to determine whether appropriate new mapping responses would be emitted. A procedure was developed to allow a fine-grain analysis of the mapping responses. Data indicated that use of continuous stimulus and response dimensions results in significant positive transfer to untrained values.

Identification Capacities of 3- to 9-Year-Old Normal Children

The effects of information load upon the identification capacity of 3-, 7-, and 9-yr.-oId normal children ( ns = 5, 4, 3) were examined. A substantial increase in transmitted information was found as a function of the mean chronological age of the three samples. Important individual differences, however, were observed within each group, which are shown to be mostly in Ss' ability to develop and to use an efficient cognitive organization of the stimulus continuum.