Principles of structure building in music,language and animal song

Human language, music and a variety of animal vocalizations constitute ways of sonic communication that exhibit remarkable structural complexity. While the complexities of language and possible parallels in animal communication have been discussed intensively, reflections on the complexity of music and animal song, and their comparisons, are underrepresented. In some ways, music and animal songs are more comparable to each other than to language as propositional semantics cannot be used as indicator of communicative success or wellformedness, and notions of grammaticality are less easily defined. This review brings together accounts of the principles of structure building in music and animal song. It relates them to corresponding models in formal language theory, the extended Chomsky hierarchy (CH), and their probabilistic counterparts. We further discuss common misunderstandings and shortcomings concerning the CH and suggest ways to move beyond. We discuss language, music and animal song in the context of their function and motivation and further integrate problems and issues that are less commonly addressed in the context of language, including continuous event spaces, features of sound and timbre, representation of temporality and interactions of multiple parallel feature streams. We discuss these aspects in the light of recent theoretical, cognitive, neuroscientific and modelling research in the domains of music, language and animal song.     

Music recognition by Japanese children with cochlear implants

Congenitally deaf Japanese children with cochlear implants were tested on their recognition of theme songs from television programs that they watched regularly. The children, who were 4-9 years of age, attempted to identify each song from a closed set of alternatives. Their song identification ability was examined in the context of the original commercial recordings (vocal plus instrumental), the original versions without the words (i.e., karaoke versions), and flute versions of the melody. The children succeeded in identifying the music only from the original versions, and their performance was related to their music listening habits. Children gave favorable appraisals of the music even when they were unable to recognize it. Further research is needed to find means of enhancing cochlear implants users' perception and appreciation of music.     

Response to vocal music in Angelman syndrome contrasts with Prader-Willi syndrome

Parent-offspring conflict—conflict over resource distribution within families due to differences in genetic relatedness—is the biological foundation for many psychological phenomena. In genomic imprinting disorders, parent-specific genetic expression is altered, causing imbalances in behaviors influenced by parental investment. We use this natural experiment to test the theory that parent-offspring conflict contributed to the evolution of vocal music by moderating infant demands for parental attention. Individuals with Prader-Willi syndrome, a genomic imprinting disorder resulting from increased relative maternal genetic contribution, show enhanced relaxation responses to song, consistent with reduced demand for parental investment (Mehr, Kotler, Howard, Haig, & Krasnow, 2017, Psychological Science). We report the necessary complementary pattern here: individuals with Angelman syndrome, a genomic imprinting disorder resulting from increased relative paternal genetic contribution, demonstrate a relatively reduced relaxation response to song, suggesting increased demand for parental attention. These results support the extension of genetic conflict theories to psychological resources like parental attention.     

The politics of “understanding”: secrecy,language, and Manouche song

This article explores how song operates as a forum through which Alsatian Manouches (a subgroup of Romanies/“Gypsies”) negotiate social relations with non-Manouches and with each other. Two of the most salient identity markers for Manouches are music and language. Whereas Manouches regard instrumental music as a legitimate means of engaging with non-Manouche people, it is often considered inappropriate to share their spoken dialect of Romani with others. As a combination of both, Manouche song represents a complex juncture of volition and apprehension towards their interactions with non-Manouches. Drawing on fieldwork among Manouche and non-Manouche performers, I investigate how public Manouche vocal performance ironically connotes an ambivalence towards cross-cultural sharing, and how power relations unfold through varying degrees of linguistic concealment and openness. This article theorizes the (il-)legibility of the voice in music and illustrates how song reflects Manouche language ideologies in flux.     

A Potential Metric of the Attractiveness of Bird Song to Humans

The prevalence of passerines (mostly oscines, or songbirds) in international bird trade suggests that the possession or production of a song that is attractive or desirable to people may contribute to the likelihood of a species being traded. Testing this is difficult because we lack a general and readily available metric that quantifies attractiveness of bird song to humans. We propose and validate such a metric, based on the number of sound files lodged for a species on the Xeno‐Canto website ( www.xeno-canto.org ). Our hypothesis is that species with more attractive songs are likely to be recorded more often, and so be represented more often in this online bird sound resource, all else being equal. Using a sample of North American and European passerines, we show that song repertoire size and geographic range size are consistently related to the number of recordings on Xeno‐Canto. We use these results to derive a metric (the residuals of a model of the number of recordings in Xeno‐Canto as a function of geographic range size) that may identify songs that are attractive to humans. Bird species whose songs are known to have inspired classical music, including several well known for their songs (e.g. common nightingale, European blackbird), have higher values of the metric than those that have not been referenced in classical music. The metric may help explain which bird species are present in trade, and so contribute to studies of invasion and conservation biology.     

You know what it is: learning words through listening to hip-hop

Music listeners have difficulty correctly understanding and remembering song lyrics. However, results from the present study support the hypothesis that young adults can learn African-American English (AAE) vocabulary from listening to hip-hop music. Non-African-American participants first gave free-response definitions to AAE vocabulary items, after which they answered demographic questions as well as questions addressing their social networks, their musical preferences, and their knowledge of popular culture. Results from the survey show a positive association between the number of hip-hop artists listened to and AAE comprehension vocabulary scores. Additionally, participants were more likely to know an AAE vocabulary item if the hip-hop artists they listen to use the word in their song lyrics. Together, these results suggest that young adults can acquire vocabulary through exposure to hip-hop music, a finding relevant for research on vocabulary acquisition, the construction of adolescent and adult identities, and the adoption of lexical innovations.     

THE RELATION OF BIRD SONG TO MUSIC

Bird song is considered as a primitive form of music, and as an evolutionary anticipation of human music. Evidence is seen in the use of elementary musical devices: in the avoidance of mechanical regularity (principle of the "monotony threshold"): in the learning of songs and tunes: in the partial detachment from utility, and the playful cultivation of sound production: and, finally, in the tendency of species with more elaborate and, by our criteria, more "musical" songs to spend a larger fraction of the minute, day, and year singing (the "correlation of quantity with quality"). The best singers are those with more variety and complexity in the use of elementary musical devices.     

Words and Melody Are Intertwined in Perception of Sung Words: EEG and Behavioral Evidence

Language and music, two of the most unique human cognitive abilities, are combined in song, rendering it an ecological model for comparing speech and music cognition. The present study was designed to determine whether words and melodies in song are processed interactively or independently, and to examine the influence of attention on the processing of words and melodies in song. Event-Related brain Potentials (ERPs) and behavioral data were recorded while non-musicians listened to pairs of sung words (prime and target) presented in four experimental conditions: same word, same melody; same word, different melody; different word, same melody; different word, different melody. Participants were asked to attend to either the words or the melody, and to perform a same/different task. In both attentional tasks, different word targets elicited an N400 component, as predicted based on previous results. Most interestingly, different melodies (sung with the same word) elicited an N400 component followed by a late positive component. Finally, ERP and behavioral data converged in showing interactions between the linguistic and melodic dimensions of sung words. The finding that the N400 effect, a well-established marker of semantic processing, was modulated by musical melody in song suggests that variations in musical features affect word processing in sung language. Implications of the interactions between words and melody are discussed in light of evidence for shared neural processing resources between the phonological/semantic aspects of language and the melodic/harmonic aspects of music.     

Alternative forms of song matching in song sparrows

Song matching, replying to a song with a similar song, occurs in many songbird species. Almost all investigations of song matching have been of type matching, where one bird's reply is unambiguously similar to the other's song (i.e. the same song type). In many populations, however, neighbours do not share song types, and therefore cannot type-match. We hypothesized that a bird lacking a true type match could still song-match a stimulus song with a song from his repertoire that was similar in some way the birds recognized. We tested this hypothesis in song sparrows, Melospiza melodia, in two playback experiments. We played the subject a stranger song that was similar to one or more of his songs, but a type match to none of them. In the first experiment, we used playback songs that began with two buzzes (‘double-buzz’ songs). In the second experiment, we used songs that began with a slow trill that increased in tempo ('speed-up' songs). Birds replied at rates significantly above chance with their own double-buzz, or speed-up song match to the respective types of playback. The results suggest that birds who do not share true song types, can still song-match each other. This broad-sense form of song matching may also occur in populations with low song type sharing. Copyright 2002 The Association for the Study of Animal Behaviour. Published by Elsevier Science Ltd. All rights reserved.     

Repertoires and Countersinging in Western Meadowlarks (Sturnella neglecta)

Countersinging in territorial birds has been viewed as a form of vocal contest. We studied the role of song repertoires in countersinging by western meadowlarks, Sturnella neglecta, by simultaneous observations of neighboring males. Neighbors tended to switch song types synchronously, but tendency to lead or follow in such switches did not correlate with orientation, subsequent behaviour, tendency to interact (as measured by the number of repetitions of each song type), or breeding stage. Males did not match song types, but were more likely to sing if their neighbour sang a song type that they shared. We suggest that synchronous switching is not a vocal contest in this species, but may be a form of competitive advertisement.     

Song is a reliable signal of bill morphology in Darwin's small tree finch Camarhynchus parvulus, and vocal performance predicts male pairing success

The shape and movement of the vocal tract are known to influence bird song. Current theory predicts that large bill and body size are correlated with low frequency song and slow trill rate. It is also widely accepted that song characteristics are important for mate choice by females. We investigated the relationship between bill morphology, song characteristics, and pairing success in Darwin's small tree finch Camarhynchus parvulus , on the Galapagos Islands. Contrary to predictions from a previous cross-species study on Darwin's finches, we found that individuals with larger bill size produced songs with slow trill rate, high dominant frequency, and broad frequency bandwidth, indicating that song is a reliable signal of bill morphology. Vocal performance as indicated by the deviation from an upper performance limit was higher in paired than unpaired males. Pairing was not skewed in favour of a particular bill size, and both small and large billed males that sang high performance song had high pairing success. The reliable signalling function of song has implications for female choice and territorial defence, given that both females and conspecific competitors can assess the relative size of males' bills through song, while females may use vocal performance as a signal of male quality.     

Encouraging Spontaneous Synchronisation with D-Jogger,an Adaptive Music Player That Aligns Movement and Music

In this study we explore how music can entrain human walkers to synchronise to the musical beat without being instructed to do so. For this, we use an interactive music player, called D-Jogger, that senses the user''s walking tempo and phase. D-Jogger aligns the music by manipulating the timing difference between beats and footfalls. Experiments are reported that led to the development and optimisation of four alignment strategies. The first strategy matched the music''s tempo continuously to the runner''s pace. The second strategy matched the music''s tempo at the beginning of a song to the runner''s pace, keeping the tempo constant for the remainder of the song. The third alignment starts a song in perfect phase synchrony and continues to adjust the tempo to match the runner''s pace. The fourth and last strategy additionally adjusts the phase of the music so each beat matches a footfall. The first two strategies resulted in a minor increase of steps in phase synchrony with the main beat when compared to a random playlist, the last two strategies resulted in a strong increase in synchronised steps. These results may be explained in terms of phase-error correction mechanisms and motor prediction schemes. Finding the phase-lock is difficult due to fluctuations in the interaction, whereas strategies that automatically align the phase between movement and music solve the problem of finding the phase-locking. Moreover, the data show that once the phase-lock is found, alignment can be easily maintained, suggesting that less entrainment effort is needed to keep the phase-lock, than to find the phase-lock. The different alignment strategies of D-Jogger can be applied in different domains such as sports, physical rehabilitation and assistive technologies for movement performance.     

The Development of Geographic Song Preferences in Female Song Sparrows Melospiza melodia

Previous work suggests that early learning plays a role in auditory preferences of female songbirds. We explored whether early experience shapes preferences for local geographic song in female song sparrows ( Melospiza melodia ), a species that prefers local geographic song in adulthood. We hand-reared females from two locations 450 km apart and controlled song exposure early in life. To examine the effects of experience and inherited factors on geographic song preferences, we used a counterbalanced design. Females from each location were tutored with either natal song (recorded from their location of capture) or non-natal song (recorded from the other location) and their preferences for tutor vs. non-tutor song assessed in adulthood. We also examined song preferences in isolate females reared with no song experience. We found that tutored females preferred their tutor song over non-tutor song, regardless of their capture location. Furthermore, birds not exposed to song (isolates) had no geographic song preferences. Thus, song exposure early in life clearly plays an important role in adult female preferences for local song in this species.     

Behavioural response to song and genetic divergence in two subspecies of white‐crowned sparrows (Zonotrichia leucophrys)

Divergence in sexual signals may drive reproductive isolation between lineages, but behavioural barriers can weaken in contact zones. Here, we investigate the role of song as a behavioural and genetic barrier in a contact zone between two subspecies of white‐crowned sparrows (Zonotrichia leucophrys). We employed a reduced genomic data set to assess population structure and infer the history underlying divergence, gene flow and hybridization. We also measured divergence in song and tested behavioural responses to song using playback experiments within and outside the contact zone. We found that the subspecies form distinct genetic clusters, and demographic inference supported a model of secondary contact. Song phenotype, particularly length of the first note (a whistle), was a significant predictor of genetic subspecies identity and genetic distance along the hybrid zone, suggesting a close link between song and genetic divergence in this system. Individuals from both parental and admixed localities responded significantly more strongly to their own song than to the other subspecies song, supporting song as a behavioural barrier. Putative parental and admixed individuals were not significantly different in their strength of discrimination between own and other songs; however, individuals from admixed localities tended to discriminate less strongly, and this difference in discrimination strength was explained by song dissimilarity as well as genetic distance. Therefore, we find that song acts as a reproductive isolating mechanism that is potentially weakening in a contact zone between the subspecies. Our findings also support the hypothesis that intraspecific song variation can reduce gene flow between populations.     

Changes in Song Complexity Correspond to Periods of Female Fertility in Blue Grosbeaks (Guiraca caerulea)

Song complexity is thought to be a sexually selected trait in passerine birds; however, quantifying relevant parameters of song complexity is the first step in testing the theory that song complexity is a sexually selected trait. We show here that blue grosbeak (Guiraca caerulea) males sing a single song type but the properties of that song type vary between renditions. This pattern of song delivery potentially provides females with an opportunity to assess dimensions of song complexity other then repertoire size. Here we characterize song complexity using four measures: (i) element repertoire size, (ii) proportion of distinct song variant, (iii) song versatility, and (iv) syntax consistency. We studied the functional significance of song complexity by comparing measures of song complexity before and after periods of female fertility. We found that male blue grosbeaks sing more song variants, use more versatile arrangements of elements, and maintain more syntax consistency during the fertile period of their social mate than during their social mate's non‐fertile period. These results point to a functional relationship between changes in song complexity and periods of female fertility in this species.     

Neural auditory selectivity develops in parallel with song

The zebra finch learns his song by memorizing a tutor's vocalization and then using auditory feedback to match his current vocalization to this memory, or template. The neural song system of adult and young birds responds to auditory stimuli, and exhibits selective tuning to the bird's own song (BOS). We have directly examined the development of neural tuning in the song motor system. We measured song system responses to vocalizations produced at various ages during sleep. We now report that the auditory response of the song motor system and motor output are linked early in song development. During sleep, playback of the current BOS induced a response in the song nucleus HVC during the song practice period, even when the song consisted of little more than repeated begging calls. Halfway through the sensorimotor period when the song was not yet in its final form, the response to BOS already exceeded that to all other auditory stimuli tested. Moreover, responses to previous, plastic versions of BOS decayed over time. This indicates that selective tuning to BOS mirrors the vocalization that the bird is currently producing.     

At the interface of the auditory and vocal motor systems: NIf and its role in vocal processing,production and learning

Communication between auditory and vocal motor nuclei is essential for vocal learning. In songbirds, the nucleus interfacialis of the nidopallium (NIf) is part of a sensorimotor loop, along with auditory nucleus avalanche (Av) and song system nucleus HVC, that links the auditory and song systems. Most of the auditory information comes through this sensorimotor loop, with the projection from NIf to HVC representing the largest single source of auditory information to the song system. In addition to providing the majority of HVC’s auditory input, NIf is also the primary driver of spontaneous activity and premotor-like bursting during sleep in HVC. Like HVC and RA, two nuclei critical for song learning and production, NIf exhibits behavioral-state dependent auditory responses and strong motor bursts that precede song output. NIf also exhibits extended periods of fast gamma oscillations following vocal production. Based on the converging evidence from studies of physiology and functional connectivity it would be reasonable to expect NIf to play an important role in the learning, maintenance, and production of song. Surprisingly, however, lesions of NIf in adult zebra finches have no effect on song production or maintenance. Only the plastic song produced by juvenile zebra finches during the sensorimotor phase of song learning is affected by NIf lesions. In this review, we carefully examine what is known about NIf at the anatomical, physiological, and behavioral levels. We reexamine conclusions drawn from previous studies in the light of our current understanding of the song system, and establish what can be said with certainty about NIf’s involvement in song learning, maintenance, and production. Finally, we review recent theories of song learning integrating possible roles for NIf within these frameworks and suggest possible parallels between NIf and sensorimotor areas that form part of the neural circuitry for speech processing in humans.     

Non-Vocal Shaping of Avian Song Development: Parallels to Human Speech Development

Vocal development in young male cowbirds (Molothrus ater) is sensitive to acoustical stimulation from males, but also to social feedback from female cowbirds, even though females do not sing. Juvenile males show different vocal trajectories if housed with local or distant population females. The major goal of the present study was to identify differences in the form and timing of non‐vocal cues from females during the period in early spring when juvenile males begin to sing stereotyped song and to finalize their repertoires. We housed juvenile males with either local or distant population females and no adult males. We found significant differences between the two groups of females in the use of wing stroking and in male reactions to wing strokes and gapes. There were also differences between the groups in male song performance. To understand further the potential consequences of these differences, we correlated measures of male and female responsiveness to results reported in Smith et al. (2000) on vocal ontogeny and song potency. We found that wing stroking by females was associated with a faster rate of song development and tended to relate to differences in song potency. The non‐vocal shaping seen here may represent a general mechanism for the development of vocal communication, as similar processes influence phonological development in human infants.