Constraints on infants' musical rhythm perception: effects of interval ratio complexity and enculturation

Effects of culture-specific experience on musical rhythm perception are evident by 12 months of age, but the role of culture-general rhythm processing constraints during early infancy has not been explored. Using a habituation procedure with 5- and 7-month-old infants, we investigated effects of temporal interval ratio complexity on discrimination of standard from novel musical patterns containing 200-ms disruptions. Infants were tested in three ratio conditions: simple (2:1), which is typical in Western music, complex (3:2), which is typical in other musical cultures, and highly complex (7:4), which is relatively rare in music throughout the world. Unlike adults and older infants, whose accuracy was predicted by familiarity, younger infants were influenced by ratio complexity, as shown by their successful discrimination in the simple and complex conditions but not in the highly complex condition. The findings suggest that ratio complexity constrains rhythm perception even prior to the acquisition of culture-specific biases.     

The perception of musical rhythm and metre

The occurrence of relatively long notes, and the repetition of melodic phrases are important cues to the metre, or regular beat, of a piece of music. A model of how people use this information to infer the metre of unaccompanied melodies is described here. The model is in the form of a computer program, and involves a definition of melodic repetition which encompasses repetitions that include certain kinds of variation. The program has been applied to the task of analysing the metric structure of the forty-eight fugue subjects of the Well-Tempered Clavier by J S Bach. The program is discussed in relation to other models both of musical understanding and of sequential concept learning.     

The effects of intensity and interval rhythms on the perception of auditory and visual temporal patterns

Repeating temporal patterns were presented in the auditory and visual modalities so that: (a) all elements were of equal intensity and were equally spaced in time (uniform presentation); (b) the intensity of one element was increased (accent presentation); or (c) the interval between two elements was increased (pause presentation). Intensity and interval patterning serve to segment the element sequence into repeating patterns.

For uniform presentation, pattern organization was by pattern structure, with auditory identification being faster. For pause presentation, organization was by the pauses; both auditory and visual identification were twice as fast as for uniform presentation. For auditory accent presentation, organization was by pattern structure and identification was slower than for uniform presentation. In contrast, the organization of visual accent presentation was by accents and identification was faster than for uniform presentation. These results suggest that complex stimuli, in which elements are patterned along more than one sensory dimension, are perceptually unique and therefore their identification rests on the nature of each modality.     

声调范畴感知和声调复杂度对音乐音高感知的跨领域影响

采用音高识别与区分任务, 以汉语母语者、越南语母语者和俄语母语者为研究对象, 考察了两个语言加工层面的因素, 即声调范畴感知模式以及不同语言声调系统的复杂度差异对跨领域音乐音高感知的影响。结果发现: (1)汉语和越南语两组声调语言母语者听辨结果符合范畴感知模式, 而俄语母语者是连续感知。在语言和音乐两种刺激条件下, 声调语言母语者在范畴边界宽度、范畴内区分率、范畴间区分率以及区分峰度等指标上不存在显著差异。(2)汉语和越南语两组声调语言母语者的音乐音高区分任务结果差异不显著。实验结果表明: 在行为层面, 母语声调范畴感知模式可以迁移到音乐音高感知中, 但复杂声调系统并不能促进跨领域的音乐音高精细感知。实验结果从语言对音乐音高加工影响的角度支持了“共享论”。     

Influences of the perception of self-motion on postural parameters.

We examined how spatial and temporal characteristics of the perception of self-motion, generated by constant velocity visual motion, was reflected in orientation of the head and whole body of young adults standing in a CAVE, a virtual environment that presents wide field of view stereo images with context and texture. Center of pressure responses from a force plate and perception of self-motion through orientation of a hand-held wand were recorded. The influence of the perception of self-motion on postural kinematics differed depending upon the plane and complexity of visual motion. Postural behaviors generated through the perception of self-motion appeared to contain a confluence of the cortically integrated visual and vestibular signals and of other somatosensory inputs. This would suggest that spatial representation during motion in the environment is modified by both ascending and descending controls. We infer from these data that motion of the visual surround can be used as a therapeutic tool to influence posture and spatial orientation, particularly in more visually sensitive individuals following central nervous system (CNS) impairment.     

Cross-modal interactions in the perception of musical performance

We investigate the dynamics of sensory integration for perceiving musical performance, a complex natural behavior. Thirty musically trained participants saw, heard, or both saw and heard, performances by two clarinetists. All participants used a sliding potentiometer to make continuous judgments of tension (a measure correlated with emotional response) and continuous judgments of phrasing (a measure correlated with perceived musical structure) as performances were presented. The data analysis sought to reveal relations between the sensory modalities (vision and audition) and to quantify the effect of seeing the performances on participants' overall subjective experience of the music. In addition to traditional statistics, functional data analysis techniques were employed to analyze time-varying aspects of the data. The auditory and visual channels were found to convey similar experiences of phrasing but different experiences of tension through much of the performances. We found that visual information served both to augment and to reduce the experience of tension at different points in the musical piece (as revealed by functional linear modeling and functional significance testing). In addition, the musicians' movements served to extend the sense of phrasing, to cue the beginning of new phrases, to indicate musical interpretation, and to anticipate changes in emotional content. Evidence for an interaction effect suggests that there may exist an emergent quality when musical performances are both seen and heard. The investigation augments knowledge of human communicative processes spanning language and music, and involving multiple modalities of emotion and information transfer.     

Some observations on the perception of Marroquin patterns.

Demonstrations are presented to show that the perception of structure in Marroquin patterns is disrupted if the dots comprising the pattern have opposite contrast polarity, and also if the dots comprising the pattern are separated in stereoscopic depth. It is also demonstrated that the perception of structure in a Marroquin pattern is made possible if the pattern is separated in stereoscopic depth from 'noise' dots, where the pattern structure cannot be perceived in either half of the unfused stereogram. In these respects the perception of Marroquin patterns is similar to the perception of Glass patterns. These findings are thus consistent with the proposal that the perception both of Marroquin and of Glass patterns is based on the construction of virtual lines.     

Development of perception of the unity of musical events

Infants' and young children's perception of the unity of musical events was investigated in three studies. In the first two, children watched video displays of two musicians playing different musical instruments side by side in synchrony, and heard a soundtrack in synchrony with both instruments but specific to one. The children judged which instrument was producing the music they heard. Three- to 4-year-olds differentiated instruments from different families but not instruments from the same family. Five- to 7-year-olds additionally differentiated instrument pairs differing in size and pitch range (e.g., violin, cello). In the third study, infants were presented some of the same musical events in order to assess whether specific experience with the instruments is necessary for perceiving the unity of musical events. Looking times revealed that 7- to 9-month-olds detected the correspondence of the sight and sound of some musical instruments. Specific experience with a variety of instruments is evidently not necessary for detecting correspondences of audible and visible properties and for differentiating instruments from different families.     

Children's perception of certain musical properties: scale and contour

Children's perception of scale and contour in melodies was investigated in five studies. Experimental tasks included judging transposed renditions of melodies (Studies 1 and 3), discriminating between transposed renditions of a melody (Study 2), judging contour-preserving transformations of melodies (Study 4), and judging similarity to a familiar target melody of transformations preserving rhythm or rhythm and contour (Study 5). The first and second studies showed that young children detect key transposition changes even in familiar melodies and they perceive similarity over key transpositions even in unfamiliar melodies. Young children also are sensitive to melodic contour over transformations that preserve it (Study 5), yet they distinguish spontaneously between melodies with the same contour and different intervals (Study 4). The key distance effect reported in the literature did not occur in the tasks of this investigation (Studies 1 and 3), and it may be apparent only for melodies shorter or more impoverished than those used here.     

Pitch interactions in the perception of isolated musical triads

In previous work done in our laboratory, we have investigated the perceived pitch class of isolated musical triads. We have found that as the amount of musical training increased, listeners perceptions progress, from very confused percepts of pitch class, to analytic percepts corresponding to the pitch class of the highest note in the triad, and finally to synthetic percepts corresponding to the root note for the more harmonic triad types. In the present work, we used a pitch matching technique to determine the actual pitch, rather than merely the pitch class, perceived when listeners analytically "hear out" a particular note in a major triad. There was a strong tendency for the pitch of the analytically perceived note to be displaced by as much as 60 cents in the direction of the other notes in the triad. The magnitude of this effect decreased as musical training increased, and it was also affected by the relative salience of the individual triad notes. These results have implications for the mechanism of triad perception, and for claims regarding the harmonic equivalence of triad inversions.     

Hemispheric asymmetries in the perception of musical intervals as a function of musical experience and family handedness background

This study examines the effect of musical experience and family handedness background on the categorization of musical intervals (two-note chords). Right-handed subjects, who were divided into four groups on the basis of musical training and presence (or absence) of left-handed family members, categorized musical intervals which were monaurally presented to left or right ear. The results, based on consistency and discreteness of categorization, showed: (1) Musicians' performance is superior to nonmusicians'; (2) musicians and nonmusicians differ significantly on their ear of preference; (3) family handedness background significantly affects ear of preference among musicians but not among nonmusicians.     

Enhanced production and perception of musical pitch in tone language speakers

Individuals differ markedly with respect to how well they can imitate pitch through singing and in their ability to perceive pitch differences. We explored whether the use of pitch in one’s native language can account for some of the differences in these abilities. Results from two studies suggest that individuals whose native language is a tone language, in which pitch contributes to word meaning, are better able to imitate (through singing) and perceptually discriminate musical pitch. These findings support the view that language acquisition fine-tunes the processing of critical auditory dimensions in the speech signal and that this fine-tuning can be carried over into nonlinguistic domains.     

Crossmodal interactions in the perception of expressivity in musical performance

In musical performance, bodily gestures play an important role in communicating expressive intentions to audiences. Although previous studies have demonstrated that visual information can have an effect on the perceived expressivity of musical performances, the investigation of audiovisual interactions has been held back by the technical difficulties associated with the generation of controlled, mismatching stimuli. With the present study, we aimed to address this issue by utilizing a novel method in order to generate controlled, balanced stimuli that comprised both matching and mismatching bimodal combinations of different expressive intentions. The aim of Experiment 1 was to investigate the relative contributions of auditory and visual kinematic cues in the perceived expressivity of piano performances, and in Experiment 2 we explored possible crossmodal interactions in the perception of auditory and visual expressivity. The results revealed that although both auditory and visual kinematic cues contribute significantly to the perception of overall expressivity, the effect of visual kinematic cues appears to be somewhat stronger. These results also provide preliminary evidence of crossmodal interactions in the perception of auditory and visual expressivity. In certain performance conditions, visual cues had an effect on the ratings of auditory expressivity, and auditory cues had a small effect on the ratings of visual expressivity.     

Probing the cognitive representation of musical time: structural constraints on the perception of timing perturbations.

To determine whether structural factors interact with the perception of musical time, musically literate listeners were presented repeatedly with eight-bar musical excerpts, realized with physically regular timing on an electronic piano. On each trial, one or two randomly chosen time intervals were lengthened by a small amount, and the score. The resulting detection accuracy profile across all positions in each musical excerpt showed pronounced dips in places where lengthening would typically occur in an expressive (temporally modulated) performance. False alarm percentages indicated that certain tones seemed longer a priori, and these were among the ones whose actual lengthening was easiest to detect. The detection accuracy and false alarm profiles were significantly correlated with each other and with the temporal microstructure of expert performances, as measured from sound recordings by famous artists. Thus the detection task apparently tapped into listeners' musical thought and revealed their expectations about the temporal microstructure of music performance. These expectations, like the timing patterns of actual performances, derive from the cognitive representation of musical structure, as cued by a variety of systemic factors (grouping, meter, harmonic progression) and their acoustic correlates. No simple psycho-acoustic explanation of the detection accuracy profiles was evident. The results suggest that the perception of musical time is not veridical but "warped" by the structural representation. This warping may provide a natural basis for performance evaluation: expected timing patterns sound more or less regular, unexpected ones irregular. Parallels to language performance and perception are noted.     

The effects of complexity on the perception of vibrotactile patterns.

Vibrotactile patterns were presented to subjects' left index fingerpads using the array from the Optacon. A set of simple (one-line) patterns and a set of complex (two-line) patterns were constructed so that they were equally identifiable when presented individually. In Experiment 1, discrimination performance was lower for two-line patterns than for one-line patterns. Communality, the number of lines that two patterns share in common, appeared to be the major factor in reducing discrimination performance for two-line patterns. Experiment 2 measured the time required to identify individual patterns. There was no significant difference in identification times for one- and two-line patterns, suggesting that features within a pattern were processed simultaneously. In the presence of a temporal masking stimulus (Experiment 3), two-line patterns were more difficult to identify than one-line patterns, but reaction times were similar for the two sets of patterns. The results suggest that varying complexity affects perception of patterns at later stages of processing.     

Development of the perception of musical relations: semitone and diatonic structure

In the present research we examined the development of sensitivity to two musical relations significant in Western tonal music, the semitone and diatonic structure. Infants and preschool children were tested for their detection of a semitone change in any position of a five-note melody. Two standard melodies were used, one composed of diatonic tones only and the other containing a non-diatonic tone. In Experiment 1, children from 4 to 6 years of age were superior in detecting the semitone change in the diatonic context compared with the nondiatonic context. In Experiment 2, infants 9 to 11 months of age detected the semitone change in all positions, but their performance was not influenced by diatonic context. These findings indicate that infants and children can discriminate a semitone in a musical context and that the priority of diatonic structure emerges by 4 to 6 years of age.