Familiarity overrides complexity in rhythm perception: a cross-cultural comparison of American and Turkish listeners

Despite the ubiquity of dancing and synchronized movement to music, relatively few studies have examined cognitive representations of musical rhythm and meter among listeners from contrasting cultures. We aimed to disentangle the contributions of culture-general and culture-specific influences by examining American and Turkish listeners' detection of temporal disruptions (varying in size from 50-250 ms in duration) to three types of stimuli: simple rhythms found in both American and Turkish music, complex rhythms found only in Turkish music, and highly complex rhythms that are rare in all cultures. Americans were most accurate when detecting disruptions to the simple rhythm. However, they performed less accurately but comparably in both the complex and highly complex conditions. By contrast, Turkish participants performed accurately and indistinguishably in both simple and complex conditions. However, they performed less accurately in the unfamiliar, highly complex condition. Together, these experiments implicate a crucial role of culture-specific listening experience and acquired musical knowledge in rhythmic pattern perception.     

Learning of timing patterns and the development of temporal expectations

The present study investigated the learning of a culturally unfamiliar musical rhythm, leading to the development of temporal expectations, and it explored the potential for generalization across tempi and tasks. With that aim, we adapted the serial reaction time task to examine the learning of temporal structures by an indirect method. The temporal pattern employed was based on a complex interval ratio (2:3) and compared to one based on a simple interval ratio (1:2). In the exposure phase, non-musician participants performed a two-choice speeded discrimination task that required responding by key press to each event of the simple or complex auditory pattern. Participants were not informed about the temporal regularities; their task solely concerned the discrimination task. During exposure (Experiments 1–3), response times decreased over time for both temporal patterns, but particularly for the events following the longer interval of the more complex 2:3 pattern. Exposure further influenced performance in subsequent testing phases, notably the precision of tap timing in a production task (Experiment 2) and temporal expectations in a perception task (Experiment 3). Our findings promote the new paradigm introduced here as a method to investigate the learning of temporal structures.     

Apparent motion enhances visual rhythm discrimination in infancy

Many studies have demonstrated that infants exhibit robust auditory rhythm discrimination, but research on infants' perception of visual rhythm is limited. In particular, the role of motion in infants' perception of visual rhythm remains unknown, despite the prevalence of motion cues in naturally occurring visual rhythms. In the present study, we examined the role of motion in 7-month-old infants' discrimination of visual rhythms by comparing experimental conditions with apparent motion in the stimuli versus stationary rhythmic stimuli. Infants succeeded at discriminating visual rhythms only when the visual rhythm occurred with an apparent motion component. These results support the view that motion plays a role in infants' perception of visual temporal information, consistent with the manner in which natural rhythms appear in the visual world.     

The role of rhythm in perceiving speech in noise: a comparison of percussionists,vocalists and non-musicians

The natural rhythms of speech help a listener follow what is being said, especially in noisy conditions. There is increasing evidence for links between rhythm abilities and language skills; however, the role of rhythm-related expertise in perceiving speech in noise is unknown. The present study assesses musical competence (rhythmic and melodic discrimination), speech-in-noise perception and auditory working memory in young adult percussionists, vocalists and non-musicians. Outcomes reveal that better ability to discriminate rhythms is associated with better sentence-in-noise (but not words-in-noise) perception across all participants. These outcomes suggest that sensitivity to rhythm helps a listener understand unfolding speech patterns in degraded listening conditions, and that observations of a “musician advantage” for speech-in-noise perception may be mediated in part by superior rhythm skills.     

Perception–production relationships and phase correction in synchronization with two-interval rhythms

Two experiments investigated the effects of interval duration ratio on perception of local timing perturbations, accuracy of rhythm production, and phase correction in musicians listening to or tapping in synchrony with cyclically repeated auditory two-interval rhythms. Ratios ranged from simple (1:2) to complex (7:11, 5:13), and from small (5:13 = 0.38) to large (6:7 = 0.86). Rhythm production and perception exhibited similar ratio-dependent biases: rhythms with small ratios were produced with increased ratios, and timing perturbations in these rhythms tended to be harder to detect when they locally increased the ratio than when they reduced it. The opposite held for rhythms with large ratios. This demonstrates a close relation between rhythm perception and production. Unexpectedly, however, the neutral “attractor” was not the simplest ratio (1:2 = 0.50) but a complex ratio near 4:7 (= 0.57). Phase correction in response to perturbations was generally rapid and did not show the ratio-dependent biases observed in rhythm perception and production. Thus, phase correction operates efficiently and autonomously even in synchronization with rhythms exhibiting complex interval ratios.     

Musical rhythm discrimination explains individual differences in grammar skills in children

This study considered a relation between rhythm perception skills and individual differences in phonological awareness and grammar abilities, which are two language skills crucial for academic achievement. Twenty‐five typically developing 6‐year‐old children were given standardized assessments of rhythm perception, phonological awareness, morpho‐syntactic competence, and non‐verbal cognitive ability. Rhythm perception accounted for 48% of the variance in morpho‐syntactic competence after controlling for non‐verbal IQ, socioeconomic status, and prior musical activities. Children with higher phonological awareness scores were better able to discriminate complex rhythms than children with lower scores, but not after controlling for IQ. This study is the first to show a relation between rhythm perception skills and morpho‐syntactic production in children with typical language development. These findings extend the literature showing substantial overlap of neurocognitive resources for processing music and language. A video abstract of this article can be viewed at: http://youtu.be/_lO692qHDNg     

Effects of Kindermusik training on infants’ rhythmic enculturation

Phillips‐Silver and Trainor (2005) demonstrated a link between movement and the metrical interpretation of rhythm patterns in 7‐month‐old infants. Infants bounced on every second beat of a rhythmic pattern with no auditory accents later preferred to listen to an accented version of the pattern with accents every second beat (duple or march meter), whereas infants bounced on every third beat of the same rhythmic pattern preferred to listen to a version with accents every third beat (triple or waltz meter). The present study compared infants participating in Kindermusik classes with infants not participating in music classes. In Kindermusik classes infants receive enriched experience moving to music. Following Western musical norms, the majority of the music samples in the classes are in duple meter. During the preference test, Kindermusik infants listened longer overall, indicating heightened interest in musical rhythms. Both groups listened longer to the accented version that matched how they had been bounced, but only the Kindermusik group showed a stronger preference in the case of duple bouncing than in the case of triple bouncing. We conclude that musical classes for infants can accelerate the development of culture‐specific metrical perception.     

Hearing what the body feels: auditory encoding of rhythmic movement

Phillips-Silver and Trainor (Phillips-Silver, J., Trainor, L.J., (2005). Feeling the beat: movement influences infants' rhythm perception. Science, 308, 1430) demonstrated an early cross-modal interaction between body movement and auditory encoding of musical rhythm in infants. Here we show that the way adults move their bodies to music influences their auditory perception of the rhythm structure. We trained adults, while listening to an ambiguous rhythm with no accented beats, to bounce by bending their knees to interpret the rhythm either as a march or as a waltz. At test, adults identified as similar an auditory version of the rhythm pattern with accented strong beats that matched their previous bouncing experience in comparison with a version whose accents did not match. In subsequent experiments we showed that this effect does not depend on visual information, but that movement of the body is critical. Parallel results from adults and infants suggest that the movement-sound interaction develops early and is fundamental to music processing throughout life.     

Enhanced music sensitivity in 9-month-old bilingual infants

This study explores the influence of bilingualism on the cognitive processing of language and music. Specifically, we investigate how infants learning a non-tone language perceive linguistic and musical pitch and how bilingualism affects cross-domain pitch perception. Dutch monolingual and bilingual infants of 8–9 months participated in the study. All infants had Dutch as one of the first languages. The other first languages, varying among bilingual families, were not tone or pitch accent languages. In two experiments, infants were tested on the discrimination of a lexical (N = 42) or a violin (N = 48) pitch contrast via a visual habituation paradigm. The two contrasts shared identical pitch contours but differed in timbre. Non-tone language learning infants did not discriminate the lexical contrast regardless of their ambient language environment. When perceiving the violin contrast, bilingual but not monolingual infants demonstrated robust discrimination. We attribute bilingual infants’ heightened sensitivity in the musical domain to the enhanced acoustic sensitivity stemming from a bilingual environment. The distinct perceptual patterns between language and music and the influence of acoustic salience on perception suggest processing diversion and association in the first year of life. Results indicate that the perception of music may entail both shared neural network with language processing, and unique neural network that is distinct from other cognitive functions.     

Information‐Theoretic Measures Predict the Human Judgment of Rhythm Complexity

To formalize the human judgment of rhythm complexity, we used five measures from information theory and algorithmic complexity to measure the complexity of 48 artificially generated rhythmic sequences. We compared these measurements to human prediction accuracy and easiness judgments obtained from a listening experiment, in which 32 participants guessed the last beat of each sequence. We also investigated the modulating effects of musical expertise and general pattern identification ability. Entropy rate and Kolmogorov complexity were correlated with prediction accuracy, and highly correlated with easiness judgments. A logistic regression showed main effects of musical training, entropy rate, and Kolmogorov complexity, and an interaction between musical training and both entropy rate and Kolmogorov complexity. These results indicate that information‐theoretic concepts capture some salient features of the human judgment of rhythm complexity, and they confirm the influence of musical expertise on complexity judgments.     

Music skills and the expressive interpretation of music in children with Williams-Beuren syndrome: pitch, rhythm, melodic imagery, phrasing, and musical affect.

This paper studied music in 14 children and adolescents with Williams-Beuren syndrome (WBS), a multi-system neurodevelopmental disorder, and 14 age-matched controls. Five aspects of music were tested. There were two tests of core music domains, pitch discrimination and rhythm discrimination. There were two tests of musical expressiveness, melodic imagery and phrasing. There was one test of musical interpretation, the ability to identify the emotional resonance of a musical excerpt. Music scores were analyzed by means of logistic regressions that modeled outcome (higher or lower music scores) as a function of group membership (WBS or Control) and cognitive age. Compared to age peers, children with WBS had similar levels of musical expressiveness, but were less able to discriminate pitch and rhythm, or to attach a semantic interpretation to emotion in music. Music skill did not vary with cognitive age. Musical strength in individuals with WBS involves not so much formal analytic skill in pitch and rhythm discrimination as a strong engagement with music as a means of expression, play, and, perhaps, improvisation.     

Music Skills and the Expressive Interpretation of Music in Children with Williams-Beuren Syndrome: Pitch,Rhythm, Melodic Imagery,Phrasing, and Musical Affect

This paper studied music in 14 children and adolescents with Williams-Beuren syndrome (WBS), a multi-system neurodevelopmental disorder, and 14 age-matched controls. Five aspects of music were tested. There were two tests of core music domains, pitch discrimination and rhythm discrimination. There were two tests of musical expressiveness, melodic imagery and phrasing. There was one test of musical interpretation, the ability to identify the emotional resonance of a musical excerpt. Music scores were analyzed by means of logistic regressions that modeled outcome (higher or lower music scores) as a function of group membership (WBS or Control) and cognitive age. Compared to age peers, children with WBS had similar levels of musical expressiveness, but were less able to discriminate pitch and rhythm, or to attach a semantic interpretation to emotion in music. Music skill did not vary with cognitive age. Musical strength in individuals with WBS involves not so much formal analytic skill in pitch and rhythm discrimination as a strong engagement with music as a means of expression, play, and, perhaps, improvisation.     

Language Experience Affects Grouping of Musical Instrument Sounds

Language experience clearly affects the perception of speech, but little is known about whether these differences in perception extend to non‐speech sounds. In this study, we investigated rhythmic perception of non‐linguistic sounds in speakers of French and German using a grouping task, in which complexity (variability in sounds, presence of pauses) was manipulated. In this task, participants grouped sequences of auditory chimeras formed from musical instruments. These chimeras mimic the complexity of speech without being speech. We found that, while showing the same overall grouping preferences, the German speakers showed stronger biases than the French speakers in grouping complex sequences. Sound variability reduced all participants’ biases, resulting in the French group showing no grouping preference for the most variable sequences, though this reduction was attenuated by musical experience. In sum, this study demonstrates that linguistic experience, musical experience, and complexity affect rhythmic grouping of non‐linguistic sounds and suggests that experience with acoustic cues in a meaningful context (language or music) is necessary for developing a robust grouping preference that survives acoustic variability.     

Bridging music and speech rhythm: Rhythmic priming and audio–motor training affect speech perception

Following findings that musical rhythmic priming enhances subsequent speech perception, we investigated whether rhythmic priming for spoken sentences can enhance phonological processing – the building blocks of speech – and whether audio–motor training enhances this effect. Participants heard a metrical prime followed by a sentence (with a matching/mismatching prosodic structure), for which they performed a phoneme detection task. Behavioural (RT) data was collected from two groups: one who received audio–motor training, and one who did not. We hypothesised that 1) phonological processing would be enhanced in matching conditions, and 2) audio–motor training with the musical rhythms would enhance this effect. Indeed, providing a matching rhythmic prime context resulted in faster phoneme detection, thus revealing a cross-domain effect of musical rhythm on phonological processing. In addition, our results indicate that rhythmic audio–motor training enhances this priming effect. These results have important implications for rhythm-based speech therapies, and suggest that metrical rhythm in music and speech may rely on shared temporal processing brain resources.     

Infants' discrimination of happy and sad music

Infants can detect information specifying affect in infant- and adult-directed speech, familiar and unfamiliar facial expressions, and in point-light displays of facial expressions. We examined 3-, 5-, 7-, and 9-month-olds' discrimination of musical excerpts judged by adults and preschoolers as happy and sad. In Experiment 1, using an infant-controlled habituation procedure, 3-, 5-, 7-, and 9-month-olds heard three musical excerpts that were rated as either happy or sad. Following habituation, infants were presented with two new musical excerpts from the other affect group. Nine-month-olds discriminated the musical excerpts rated as affectively different. Five- and seven-month-olds discriminated the happy and sad excerpts when they were habituated to sad excerpts but not when they were habituated to happy excerpts. Three-month-olds showed no evidence of discriminating the sad and happy excerpts. In Experiment 2, 5-, 7-, and 9-month-olds were presented with two new musical excerpts from the same affective group as the habituation excerpts. At no age did infants discriminate these novel, yet affectively similar, musical excerpts. In Experiment 3, we examined 5-, 7-, and 9-month-olds' discrimination of individual excerpts rated as affectively similar. Only the 9-month-olds discriminated the affectively similar individual excerpts. Results are discussed in terms of infants' ability to discriminate affect across a variety of events and its relevance for later social-communicative development.     

The inability of young children to reproduce intensity differences in musical rhythms

A musical rhythm can be described in terms of both its temporal and its dynamic structure. However, although 6-year-old children are able to perceive and reproduce simple temporal structures, even 8-year-olds rarely reproduce intensity differences. Four experiments on the perception and reproduction of musical rhythms by 5- to 8-year-old children demonstrate that even though dynamic structure is clearly dominated by its temporal support, intensity differences play a role in reinforcing the temporal structure. The inability of children to reproduce intensity differences appears to be due neither to an inability to control the intensity of their tap responses nor to the fact that they cannot perceive such changes in intensity. Rather, the results seem best interpreted in terms of the allocation of attentional resources. With simple stimulus material (Experiments 1-3), the children focused on temporal information, and only when the processing of temporal information was mastered did they have "enough attention left" to direct it to intensity differences (Experiment 2). With more complex orchestral music (Experiment 4), attention was primarily allocated to the dynamic structure.     

Temporal discrimination increases in precision over development and parallels the development of numerosity discrimination

Time perception is important for many aspects of human behavior, and a large literature documents that adults represent intervals and that their ability to discriminate temporal intervals is ratio dependent. Here we replicate a recent study by vanMarle and Wynn (2006) that used the visual habituation paradigm and demonstrated that temporal discrimination in 6-month-old infants is also ratio dependent. We further demonstrate that between 6 and 10 months of age temporal discrimination increases in precision such that by 10 months of age infants succeed at discriminating a 2:3 ratio, a ratio that 6-month-old infants were unable to discriminate. We discuss the potential implications of the fact that temporal discrimination follows the same developmental progression that has been previously observed for number discrimination in infancy (Lipton & Spelke, 2003).     

Sensorimotor and working memory systems jointly support development of perceptual rhythm processing

We studied the role of sensorimotor and working memory systems in supporting development of perceptual rhythm processing with 119 participants aged 7–12 years. Children were assessed for their abilities in sensorimotor synchronization (SMS; beat tapping), auditory working memory (AWM; digit span), and rhythm discrimination (RD; same/different judgment on a pair of musical rhythm sequences). Multiple regression analysis revealed that children's RD performance was independently predicted by higher beat tapping consistency and greater digit span score, with all other demographic variables (age, sex, socioeconomic status, music training) controlled. The association between RD and SMS was more robust in the slower tempos (60 and 100 beats-per-minute (BPM)) than faster ones (120 and 180 BPM). Critically, the relation of SMS to RD was moderated by age in that RD performance was predicted by beat tapping consistency in younger children (age: 7–9 years), but not in older children (age: 10–12 years). AWM was the only predictor of RD in older children. Together, the current findings demonstrate that the sensorimotor and working memory systems jointly support RD processing during middle-to-late childhood and that the degree of association between the two systems and perceptual rhythm processing is shifted before entering into early adolescence.     

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.     

The effect of support ratio on infants' perception of illusory contours

We used a preferential looking technique to investigate the effect of support ratio (a ratio of the physically specified contours to the total edge length) on the perception of Kanizsa illusory contours in infants aged 3-8 months. Previous work has shown that for adult observers the illusory-contour strength increases proportionally with the support ratio. When the support ratio was relatively high (66%), infants preferred illusory contours to non-illusory figures by 3-4 months of age (experiment 1). In contrast, only infants 7-8 months old showed this preference for illusory contours when the support ratio was reduced to 37% (experiment 3). Further, infants showed no preference for an outline version of the illusory-contour figure, which produced no illusory contours (experiment 2). This result confirms that the infants' preference reflects their perception of illusory contours. Our results show that (i) illusory-contour perception emerges at around 3-4 months of age, but (ii) that this ability is very limited until around 7-8 months of age.