Erin E. Hannon

Music acquisition: effects of enculturation and formal training on development

Musical structure is complex, consisting of a small set of elements that combine to form hierarchical levels of pitch and temporal structure according to grammatical rules. As with language, different systems use different elements and rules for combination. Drawing on recent findings, we propose that music acquisition begins with basic features, such as peripheral frequency-coding mechanisms and multisensory timing connections, and proceeds through enculturation, whereby everyday exposure to a particular music system creates, in a systematic order of acquisition, culture-specific brain structures and representations. Finally, we propose that formal musical training invokes domain-specific processes that affect salience of musical input and the amount of cortical tissue devoted to its processing, as well as domain-general processes of attention and executive functioning.

Infants use meter to categorize rhythms and melodies: Implications for musical structure learning

Little is known about whether infants perceive meter, the underlying temporal structure of music. We employed a habituation paradigm to examine whether 7-month-old infants could categorize rhythmic and melodic patterns on the basis of the underlying meter, which was implied from event and accent frequency of occurrence. In Experiment 1, infants discriminated duple and triple classes of rhythm on the basis of implied meter. Experiment 2 replicated this result while controlling for rhythmic grouping structure, confirming that infants perceived metrical structure despite occasional ambiguities and conflicting group structure. In Experiment 3, infants categorized melodies on the basis of contingencies between metrical position and pitch. Infants presented with metrical melodies detected reversals of pitch/meter contingencies, while infants presented with non-metrical melodies showed no preference. Results indicate that infants can infer meter from rhythmic patterns, and that they may use this metrical structure to bootstrap their knowledge acquisition in music learning.

Effects of context on auditory stream segregation.

The authors examined the effect of preceding context on auditory stream segregation. Low tones (A), high tones (B), and silences (-) were presented in an ABA- pattern. Participants indicated whether they perceived 1 or 2 streams of tones. The A tone frequency was fixed, and the B tone was the same as the A tone or had 1 of 3 higher frequencies. Perception of 2 streams in the current trial increased with greater frequency separation between the A and B tones (Delta f). Larger Delta f in previous trials modified this pattern, causing less streaming in the current trial. This occurred even when listeners were asked to bias their perception toward hearing 1 stream or 2 streams. The effect of previous Delta f was not due to response bias because simply perceiving 2 streams in the previous trial did not cause less streaming in the current trial. Finally, the effect of previous ?f was diminished, though still present, when the silent duration between trials was increased to 5.76 s. The time course of this context effect on streaming implicates the involvement of auditory sensory memory or neural adaptation.

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.

Effects of perceptual experience on children's and adults' perception of unfamiliar rhythms

Rhythm and meter are fundamental components of music that are universal yet also culture specific. Although simple, isochronous meters are preferred and more readily discriminated than highly complex, nonisochronous meters, moderately complex nonisochronous meters do not pose a problem for listeners who are exposed to them from a young age. The present work uses a behavioral task to examine the ease with which listeners of various ages acquire knowledge of unfamiliar metrical structures from passive exposure. We examined perception of familiar (Western) rhythms with an isochronous meter and unfamiliar (Balkan) rhythms with a nonisochronous meter. We compared discrimination by American children (5 to 11 years) and adults before and after a 2‐week period of at‐home listening to nonisochronous meter music from Bulgaria. During the first session, listeners of all ages exhibited superior discrimination of isochronous than in nonisochronous melodies. Across sessions, this asymmetry declined for young children but not for older children and adults.

Perceiving Speech Rhythm in Music: Listeners Classify Instrumental Songs According to Language of Origin.

Recent evidence suggests that the musical rhythm of a particular culture may parallel the speech rhythm of that cultures language (Patel, A. D., & Daniele, J. R. (2003). An empirical comparison of rhythm in language and music. Cognition, 87, B35-B45). The present experiments aimed to determine whether listeners actually perceive such rhythmic differences in a purely musical context (i.e., in instrumental music without words). In Experiment 1a, listeners successfully classified instrumental renditions of French and English songs having highly contrastive rhythmic differences. Experiment 1b replicated this result with the same songs containing rhythmic information only. In Experiments 2a and 2b, listeners successfully classified original and rhythm-only stimuli when language-specific rhythmic differences were less contrastive but more representative of differences found in actual music and speech. These findings indicate that listeners can use rhythmic similarities and differences to classify songs originally composed in two languages having contrasting rhythmic prosody.

Finding the music of speech: Musical knowledge influences pitch processing in speech

Few studies comparing music and language processing have adequately controlled for low-level acoustical differences, making it unclear whether differences in music and language processing arise from domain-specific knowledge, acoustic characteristics, or both. We controlled acoustic characteristics by using the speech-to-song illusion, which often results in a perceptual transformation to song after several repetitions of an utterance. Participants performed a same-different pitch discrimination task for the initial repetition (heard as speech) and the final repetition (heard as song). Better detection was observed for pitch changes that violated rather than conformed to Western musical scale structure, but only when utterances transformed to song, indicating that music-specific pitch representations were activated and influenced perception. This shows that music-specific processes can be activated when an utterance is heard as song, suggesting that the high-level status of a stimulus as either language or music can be behaviorally dissociated from low-level acoustic factors.

Linking prenatal experience to the emerging musical mind

The musical brain is built over time through experience with a multitude of sounds in the auditory environment. However, learning the melodies, timbres, and rhythms unique to the music and language of one’s culture begins already within the mother’s womb during the third trimester of human development. We review evidence that the intrauterine auditory environment plays a key role in shaping later auditory development and musical preferences. We describe evidence that externally and internally generated sounds influence the developing fetus, and argue that such prenatal auditory experience may set the trajectory for the development of the musical mind.

11 – Musical Development

Music is a species-specific communication system that develops under a complex set of genetic constraints and environmental input. As with language, some features of musical perception, such as the use of hierarchical pitch and time structures to organize successive sound events, appear to be essentially universal and rest on general capacities and constraints of the human nervous system. And, similar to language, many different musical systems exist, such that through exposure, participation, and/or formal musical training, children become specialized for processing the structure of the musical system(s) in their environment (see Sections III and IV). During the past couple of decades, research has revealed that the process of becoming specialized for processing the musical structure of one’s culture begins early in development and takes many years to complete. Humans are among the most immature animals at birth and have one of the relatively longest periods of development. Although human adults are very similar to other primates in terms of genetic makeup, they have relatively complex brains with large cerebral cortices. This outcome appears to be achieved in large part by an extended period of experience-driven neural plasticity. This extended period of development likely contributes to the unique capacity of humans for generative communication systems, such as music and language, in which novel melodies or utterances are commonly produced. This generative quality also contributes to the cultural changeability of music systems, such that each generation can modify the structural rules of their musical system and incorporate features from foreign musical systems to create new genres. From an evolutionary perspective, music presents a difficult case, a fact that was recognized even by Darwin (1871), who wrote that music was among the most mysterious faculties of the human species as its adaptive survival value is not clear. Many theoretical perspectives have been proposed since Darwin (e.g., Dissanayake, 2000, 2008; Falk, 2004, 2009; Fitch, 2006; Huron, 2001, 2006; Justus & Hutsler, 2005; McDermott & Hauser, 2005; Miller, 2000; Trainor, 2006; Trehub & Trainor, 1998; Wallin, Merker, & Brown, 2000). According to Pinker (1997), music serves no

Babies know bad dancing when they see it: Older but not younger infants discriminate between synchronous and asynchronous audiovisual musical displays

Movement to music is a universal human behavior, yet little is known about how observers perceive audiovisual synchrony in complex musical displays such as a person dancing to music, particularly during infancy and childhood. In the current study, we investigated how perception of musical audiovisual synchrony develops over the first year of life. We habituated infants to a video of a person dancing to music and subsequently presented videos in which the visual track was matched (synchronous) or mismatched (asynchronous) with the audio track. In a visual-only control condition, we presented the same visual stimuli with no sound. In Experiment 1, we found that older infants (8-12months) exhibited a novelty preference for the mismatched movie when both auditory information and visual information were available and showed no preference when only visual information was available. By contrast, younger infants (5-8months) in Experiment 2 did not discriminate matching stimuli from mismatching stimuli. This suggests that the ability to perceive musical audiovisual synchrony may develop during the second half of the first year of infancy.