Stephen Handel

The meter of syncopated auditory polyrhythms

Subjects tapped the perceived meter or beat of polyrhythms that consisted of two conflicting pulse trains (e.g., three elements/repetition vs. five elements/repetition). The meter interpretation was based on the global rhythmic properties of a polyrhythm as well as on the temporal properties of each pulse train. The rhythmic properties of a polyrhythm restricted the range of meter interpretations. Some polyrhythms were overdetermined and allowed but one meter, while others were more ambiguous and allowed several meters. For all polyrhythms, however, the temporal interval between elements of a pulse train determined whether that pulse train would serve as the background beat. These results demonstrate the value of a hierarchic analysis of rhythm

Similarity and Features of Natural Textures

In 3 experiments the type of model that is best for conceptualizing the attentive similarity of natural textures was investigated. Different groups of participants placed pictures into groups however they wished, described the resulting clusters and multidimensional scaling dimensions, identified the objects or surfaces depicted in the pictures, and ranked the pictures along several hypothesized attribute-based dimensions. Results indicate that similarity is context dependent, that natural textures seem to be organized according to family resemblances, and that a dimensional model is inappropriate. These outcomes suggest that models of preattentive segregation and attentive cognition may be incommensurable.

The contextual nature of rhythmic interpretation

Five experiments investigated the rhythmic interpretation of polyrhythms that consisted of two or three conflicting pulse trains (e.g., three elements/repetition vs. four elements/repetition vs. five elements/repetition). The preferred rhythms were eithermeter rhythms, in which one pulse train served as the background controlling beat breaking the repetition (i.e., measure) into equal parts, orcross-rhythms, in which two or three pulse trains were integrated into a fore-ground melodic rhythm. The choice among various meter rhythms and various cross-rhythms was contextual, being based on the polyrhythm configuration, the timing between elements of each pulse train, the frequency of the elements of each pulse train, as well as the duration or intensity accentuation of the elements of each pulse train. In addition, there were consistent individual differences in strategies for rhythmic interpretation. The diversity of rhythmic interpretations occurs only with sufficiently dense stimuli, and both experimentation and theorizing must approach this level of complexity.

The effect of tempo and tone duration on rhythm discrimination

Rhythm constancy was investigated in two experiments. In Experiment 1, the first rhythm was presented at one tempo, the second rhythm was presented at a different tempo, and subjects judged whether the relative timing structures were identical (i.e., was the first rhythm merely sped up or slowed down to generate the second rhythm?). For the nonmetric rhythms used here, subjects perceived the rhythm in terms of the figural grouping of the tones, and rhythm constancy broke down between slower and faster tempos. In Experiment 2, the first rhythm was presented in tones of one duration; the second rhythm was presented in tones of a different duration; and subjects judged whether the timing structures of the tone onsets were identical (the two rhythms were presented at the same tempo). These results indicated a high degree of constancy; subjects found it easy to discriminate the timing structures. These results confirm that the onset timing is critical to rhythm perception and suggest that rhythm perception at slower rates (2 elements/sec) differs from rhythm perception at faster rates (3–4 elements/sec).

Using Polyrhythms to Study Rhythm

Polyrhythms consisting of two or three dissonant pulse trains have been used to investigate rhythmic interpretation. The dissonant rhythmic lines allow for the study of the emergent nature of rhythmic organization. The empirical outcomes demonstrated that the rhythm perceived was contextual, depending on the timing between elements, pulse train frequency, polyrhythm configuration, element accentuation, and individual preferences. The effect of any factor depended on the values of each other factor. Although polyrhythms can illustrate the interactive nature of rhythm, polyrhythms do not shed light on the traditional views of rhythm concerning grouping and temporal extrapolation. Therefore, polyrhythms provide a good context for studying rhythm as a foreground melody at the expense of providing a poor context for studying rhythm as a background-organizing factor for tonal melody.

Space is to time as vision is to audition: seductive but misleading

Space and time serve two perceptual functions. First, space/time forms a framework for visual and auditory events. Second, spatial and temporal change defines the properties of events and objects. It is at this second level that correspondences (i.e., mappings) between visual and auditory qualities can be hypothesized. Due to the active nature of perceiving, all such mappings illustrate the possible relations between looking and listening. Language: en

The Role of Pattern Goodness in the Reproduction of Backward Masked Patterns.

Four experiments investigated the role of pattern goodness in backward masking using five- and four-dot patterns constructed by placing dots in the cells of a 3 x 3 matrix. In Experiment 1, subjects rated the goodness of these patterns and the results replicated previous work showing that good patterns had few alternatives. In Experiment 2, the dot patterns were the target stimuli in a backward masking task using a variety of masking stimuli. For all masking, good patterns were reproduced more accurately than poor patterns. In Experiment 3, the goodness of the masking stimulus was varied. The results indicated that good patterns were reproduced more accurately (replicating Experiment 2) and that good patterns were less effective as stimulus than were poor patterns. In Experiment 4, a long interstimulus interval which precluded masking was used to determine whether goodness affected encoding or memory. At these intervals, there were no differences among patterns, suggesting that the effect of pattern goodness was on rate of encoding. These results demonstrate the importance of configural properties in pattern perception.

The differentiation of rhythmic structure

Listeners judged whether two five-tone nonmetric rhythms were the same or different. Each rhythm was presented one, two, or four times to study the process of perceptual differentiation. The results indicated that the listeners perceived these rhythms in-terms.of the grouping of the tones, and not in terms of the timing between the groups. Two rhythms that had the same perceptual grouping were judged as being identical, even if the timing between the groups was different. The perception of the groupings of tones developed gradually. If each rhythm was presented only once, then the listeners had only a global percept, focused on groups (runs) of three elements, and often judged two different rhythms as being identical. If the rhythms were presented two or four times, then the grouping of the tones became more differentiated and the listeners were less likely to judge different patterns as being identical. Thus, perception of auditory rhythmic structure appears to follow the same developmental process as the perception of visual spatial structure.

Syncopated auditory polyrhythms: Discontinuous reversals in meter interpretation

Subjects tapped the beat (i.e., meter) of a polyrhythm in which one tone occurred three times per pattern repitition while the second tone occurred four times per pattern repitition. At one presentation rate, the polyrhythm underwent a figure‐ground reversal —the beat shifted from one tone to the other. Rhythmic organization is thus a function of the absolute tempo.

Effect of rhythmic grouping on stream segregation.

Three experiments investigated the role of temporal grouping on auditory stream segregation. For sounds that formed frequency streams (e.g., 400 Hz, 500 Hz, 1600 Hz, and 2000 Hz), the effect of rhythm was minimal. Temporal grouping did not affect judgments of stream segregation and did not affect difficulty of sequence identification. In contrast, for sounds that tended to form one coherent sequence (e.g., 750 Hz, 1500 Hz, 3000 Hz, and 6000 Hz), temporal grouping affected judgments of stream segregation as well as difficulty of identification. The temporal grouping could space the three lower or three higher pitch tones equally in time and this induced isochronous stream segregation. Subjects could not interleave the resulting streams, and identification became far more difficult. The role of rhythmic grouping is therefore contextual, depending on the relationships between the elements as well as the order of the elements.