Preference for consonant music over dissonant music by an infant chimpanzee

It has been shown that humans prefer consonant sounds from the early stages of development. From a comparative psychological perspective, although previous studies have shown that birds and monkeys can discriminate between consonant and dissonant sounds, it remains unclear whether nonhumans have a spontaneous preference for consonant music over dissonant music as humans do. We report here that a five-month-old human-raised chimpanzee (Pan troglodytes) preferred consonant music. The infant chimpanzee consistently preferred to produce, with the aid of our computerized setup, consonant versions of music for a longer duration than dissonant versions. This result suggests that the preference for consonance is not unique to humans. Further, it supports the hypothesis that one major basis of musical appreciation has some evolutionary origins.     

Do Women Prefer More Complex Music around Ovulation?

The evolutionary origins of music are much debated. One theory holds that the ability to produce complex musical sounds might reflect qualities that are relevant in mate choice contexts and hence, that music is functionally analogous to the sexually-selected acoustic displays of some animals. If so, women may be expected to show heightened preferences for more complex music when they are most fertile. Here, we used computer-generated musical pieces and ovulation predictor kits to test this hypothesis. Our results indicate that women prefer more complex music in general; however, we found no evidence that their preference for more complex music increased around ovulation. Consequently, our findings are not consistent with the hypothesis that a heightened preference/bias in women for more complex music around ovulation could have played a role in the evolution of music. We go on to suggest future studies that could further investigate whether sexual selection played a role in the evolution of this universal aspect of human culture.     

Genetic explorations of recent human metabolic adaptations: hypotheses and evidence

Since humans and chimpanzees split from a common ancestor over 6 million years ago, human metabolism has changed dramatically. This change includes adaptations to a high-quality diet, the evolution of an energetically expensive brain, dramatic increases in endurance abilities, and capacity for energy storage in white adipose tissue. Human metabolism continues to evolve in modern human populations in response to local environmental and cultural selective forces. Understanding the nature of these selective forces and the physiological responses during human evolution is a compelling challenge for evolutionary biologists. The complex genetic architecture surrounding metabolic phenotypes indicates that selection probably altered allelic frequencies across many loci in populations experiencing adaptive metabolic change to fit their environment. A recent analysis supports this hypothesis, finding that classic selective sweeps at single loci were rare during the past 250 000 years of human evolution. Detection of selective signatures at multiple loci, as well as exploration of physiological adaptation to environment in humans, will require cross-disciplinary collaboration, including the incorporation of biological pathway analysis. This review explores the Thrifty Genotype Hypothesis, high-altitude adaptation, cold-resistance adaptation, and genetic evidence surrounding these proposed metabolic adaptations in an attempt to clarify current challenges and avenues for future progress.     

Prolegomenon for a hypothesis on music as expression of an evolutionary early homeostatic feedback-mechanism. A biomusicological proposal.

Musical experience and creativity are regarded to be largely depending on cultural conditions and hence on higher cognitive functions. True as this may be, there are, however, numerous responses to music-the urge to make music taken into account-which derive from deeper levels of the human organism, namely from arousing alternatively moderating vegetative and limbic functions. Although the behavioral intensity and quality emanating from such evolutionary early nervous structures may be affected by cultural influence, they still seem to be essentially independent. Similar specific responses to acoustical and/or motor patterned stimuli are found among some other higher vertebrates which like humans are equipped with sophisticated mechanisms for hearing, sound production and locomotion, well tuned to each other. However, it is even today an open question whether these manifestations of auditive-phonatory-locomotor abilities just are analogues or if they share a common evolutionary background. The current discussion on this matter has accumulated data which apparently support the latter view pointing to that sexual selection would be the common force, first suggested by Charles Darwin (153). Other, and still more recent data in genetics and neuroscience, may be interpreted as hints at that the common origin would be a more elemental organismic feature, a metabolic-homeostatic variable which due to its evolutionary strength eventually created the platform for a radiation of adaptations concerning species-specific patterned sounds and locomotions with a broad spectrum of tasks, among them sexual selection. This line of reasoning is here, under reference to recent biological data, made the basis for a hypothetical model of music as an expression of an early homeostatic feedback mechanism. Accordingly, in music there is a central variable, a “heart” or a “core”, which is not to be found exclusively in music but appears globally as a releasing mechanism for basic endocrine, autonomous and elementally cognitive functions. It is of acoustical or motoric nature, or of a combination of these characters, and is performed in repetitive trains of impulses. It is further assumed that the target of its operations is mainly proteins with a regulatory effect on the cellular and synaptic states. The principal representatives for these proteins are growth factors, especially the NGF which originally was regarded as a growth stimulator within the peripheral and sympathetical systems but which eventually appeared to be also a synergetic modulator of neuro-endocrine-immuno-reactions, i.e. of the three central homeostatic systems (5, 80). One can speculate that this variable is functionally active at an elemental level such that it has escaped to be knocked out by forceful “higher” and evolutionary younger factors (49:13). This hypothesis — that music has its roots within and is a part of a globally occurring natural acoustical-motoric stimulus, manifested in a great variety of auditory and motoric behavior in humans and among some other higher vertebrates — implies that humankind has developed this stimulus into a category of acoustical structures which oscillate round an instable point of equilibrium. Exactly such structures, not stochastic but neither too predictable, affect the organism mainly on a sensory-vegetative level (59, 102, 137, 151). They are in addition perceptionally optimal in creating cortical space-temporal neural patterns with strong interhemispheric coherence (110, 130). According to this scenario, music did not originate from a human need of communication or as an aspect of sexual selection. It emerged from elemental processes within the individual organism with the aspiration to maintain his bodily and mental fitness, thus on a pre-social level. What was beneficial to the single individual in his fight for survival, was good also for the group and its survival. Starting from that platform music has evolved in symbiosis with dance and play within a large spectrum of social functions, where sexual selection and ritual and autonomously aesthetical tasks got a focal role that increased over time and always was accompanied by emotional events. Behind, the ticking in the deep structure of music of this in cultural-ethical terms totally value-neutral archaic mechanism goes on without pause, contributing to the maintenance of an optimal functional balance in body and mind of the individual, and the group as well.     

Cultural Evolution

SYNOPSIS. Culture is made possible by the existence of mechanismsof learning and communication. Because of it, we can profitfrom the experience and ideas of others. It is convenient toinclude in it tools, technologies, and all culturally transmittedbehaviors. At least from an evolutionary point of view, theyshare common mechanisms. It is also becoming increasingly clearthatanimals share with us potential for cultural adaptation, whichis however much more highlydeveloped in humans, as shown forinstance, by the extension of human brain areas that are involvedin control of hand and phonation organs. To understand how culture evolves one can make resort to modelsthat map reasonably well after the necessary substitutions,into those that havebeen useful in biology. A major differencethat one finds is in mechanisms of transmission, which are muchmore varied in culture than in biology. Parent-child (vertical)transmission is present in both. An "infectious" (horizontal)mechanism is characteristic of cultural transmission, but ispractically absent in the genetic case. Other mechanisms oftransmission are reviewed, along with their evolutionary consequences.The variety of these mechanisms can make culture extremely fastand flexible, and there are the great advantages of culturaladaptation vs. genetic adaptation by natural selection, or vs.physiological adaptations (which are relatively fast but highlyspecific: for instance, tanning under exposure to UV). But culturecan also be extremely conservative. Also, some cultural transmissionmechanisms allow heterogeneitybetween individuals to persist,others tend to make populations extremely homogeneous. The study of culture from an evolutionary point of view is young,but very promising.     

Natural pedagogy as evolutionary adaptation

We propose that the cognitive mechanisms that enable the transmission of cultural knowledge by communication between individuals constitute a system of 'natural pedagogy' in humans, and represent an evolutionary adaptation along the hominin lineage. We discuss three kinds of arguments that support this hypothesis. First, natural pedagogy is likely to be human-specific: while social learning and communication are both widespread in non-human animals, we know of no example of social learning by communication in any other species apart from humans. Second, natural pedagogy is universal: despite the huge variability in child-rearing practices, all human cultures rely on communication to transmit to novices a variety of different types of cultural knowledge, including information about artefact kinds, conventional behaviours, arbitrary referential symbols, cognitively opaque skills and know-how embedded in means-end actions. Third, the data available on early hominin technological culture are more compatible with the assumption that natural pedagogy was an independently selected adaptive cognitive system than considering it as a by-product of some other human-specific adaptation, such as language. By providing a qualitatively new type of social learning mechanism, natural pedagogy is not only the product but also one of the sources of the rich cultural heritage of our species.     

Experience Changes How Emotion in Music Is Judged: Evidence from Children Listening with Bilateral Cochlear Implants,Bimodal Devices,and Normal Hearing

Children using unilateral cochlear implants abnormally rely on tempo rather than mode cues to distinguish whether a musical piece is happy or sad. This led us to question how this judgment is affected by the type of experience in early auditory development. We hypothesized that judgments of the emotional content of music would vary by the type and duration of access to sound in early life due to deafness, altered perception of musical cues through new ways of using auditory prostheses bilaterally, and formal music training during childhood. Seventy-five participants completed the Montreal Emotion Identification Test. Thirty-three had normal hearing (aged 6.6 to 40.0 years) and 42 children had hearing loss and used bilateral auditory prostheses (31 bilaterally implanted and 11 unilaterally implanted with contralateral hearing aid use). Reaction time and accuracy were measured. Accurate judgment of emotion in music was achieved across ages and musical experience. Musical training accentuated the reliance on mode cues which developed with age in the normal hearing group. Degrading pitch cues through cochlear implant-mediated hearing induced greater reliance on tempo cues, but mode cues grew in salience when at least partial acoustic information was available through some residual hearing in the contralateral ear. Finally, when pitch cues were experimentally distorted to represent cochlear implant hearing, individuals with normal hearing (including those with musical training) switched to an abnormal dependence on tempo cues. The data indicate that, in a western culture, access to acoustic hearing in early life promotes a preference for mode rather than tempo cues which is enhanced by musical training. The challenge to these preferred strategies during cochlear implant hearing (simulated and real), regardless of musical training, suggests that access to pitch cues for children with hearing loss must be improved by preservation of residual hearing and improvements in cochlear implant technology.     

Cross-cultural perspectives on music and musicality

Musical behaviours are universal across human populations and, at the same time, highly diverse in their structures, roles and cultural interpretations. Although laboratory studies of isolated listeners and music-makers have yielded important insights into sensorimotor and cognitive skills and their neural underpinnings, they have revealed little about the broader significance of music for individuals, peer groups and communities. This review presents a sampling of musical forms and coordinated musical activity across cultures, with the aim of highlighting key similarities and differences. The focus is on scholarly and everyday ideas about music—what it is and where it originates—as well the antiquity of music and the contribution of musical behaviour to ritual activity, social organization, caregiving and group cohesion. Synchronous arousal, action synchrony and imitative behaviours are among the means by which music facilitates social bonding. The commonalities and differences in musical forms and functions across cultures suggest new directions for ethnomusicology, music cognition and neuroscience, and a pivot away from the predominant scientific focus on instrumental music in the Western European tradition.     

Musical improvisation skill in a prospective partner is associated with mate value and preferences,consistent with sexual selection and parental investment theory: Implications for the origin of music

Music is a human universal, which suggests a biological adaptation. Several evolutionary explanations have been proposed, covering the entire spectrum of natural, sexual, and group selection. Here we consider the hypothesis that musical behaviour constitutes a reliable or even costly signal of fitness, and thus may have evolved as a human trait through sexual selection. We experimentally tested how musical performance quality (MPQ), in improvisations on the drums, saxophone, and violin, affects mate values and mate preferences perceived by a prospective partner. Swedish student participants (27 of each sex) saw a face of a person of the opposite sex and heard a piece of improvised music being played. The music occurred in three levels of MPQ and the faces in three levels of facial attractiveness (FA). For each parametric combination of MPG and FA, the participants rated four mate value scales (intelligence, health, social status, and parenting skill) and four mate preference scales (date, intercourse, and short- and long term relationship). Consistent with sexual selection theory, mate value ratings were generally increased by MPQ for raters of both sexes. Consistent with more specific hypotheses that follow from combining sexual selection and parental investment theory, women’s but not men’s preference for a long-term, but not short-term, relationship was significantly increased by MPQ, MPQ generally affected women’s ratings more than men’s, FA generally affected men’s ratings more than women’s, and women’s ratings of intelligence were even more influenced by MPQ than by FA.     

Expression of emotion in Eastern and Western music mirrors vocalization

In Western music, the major mode is typically used to convey excited, happy, bright or martial emotions, whereas the minor mode typically conveys subdued, sad or dark emotions. Recent studies indicate that the differences between these modes parallel differences between the prosodic and spectral characteristics of voiced speech sounds uttered in corresponding emotional states. Here we ask whether tonality and emotion are similarly linked in an Eastern musical tradition. The results show that the tonal relationships used to express positive/excited and negative/subdued emotions in classical South Indian music are much the same as those used in Western music. Moreover, tonal variations in the prosody of English and Tamil speech uttered in different emotional states are parallel to the tonal trends in music. These results are consistent with the hypothesis that the association between musical tonality and emotion is based on universal vocal characteristics of different affective states.     

Music and dance as a coalition signaling system

Evidence suggests that humans might have neurological specializations for music processing, but a compelling adaptationist account of music and dance is lacking. The sexual selection hypothesis cannot easily account for the widespread performance of music and dance in groups (especially synchronized performances), and the social bonding hypothesis has severe theoretical difficulties. Humans are unique among the primates in their ability to form cooperative alliances between groups in the absence of consanguineal ties. We propose that this unique form of social organization is predicated on music and dance. Music and dance may have evolved as a coalition signaling system that could, among other things, credibly communicate coalition quality, thus permitting meaningful cooperative relationships between groups. This capability may have evolved from coordinated territorial defense signals that are common in many social species, including chimpanzees. We present a study in which manipulation of music synchrony significantly altered subjects’ perceptions of music quality, and in which subjects’ perceptions of music quality were correlated with their perceptions of coalition quality, supporting our hypothesis. Our hypothesis also has implications for the evolution of psychological mechanisms underlying cultural production in other domains such as food preparation, clothing and body decoration, storytelling and ritual, and tools and other artifacts. Edward Hagen is a research scientist at the Institute for Theoretical Biology, Humboldt University, Berlin. Gregory Bryant is a doctoral candidate in the Department of Psychology, University of California, Santa Cruz.     

Culture and the evolution of human cooperation

The scale of human cooperation is an evolutionary puzzle. All of the available evidence suggests that the societies of our Pliocene ancestors were like those of other social primates, and this means that human psychology has changed in ways that support larger, more cooperative societies that characterize modern humans. In this paper, we argue that cultural adaptation is a key factor in these changes. Over the last million years or so, people evolved the ability to learn from each other, creating the possibility of cumulative, cultural evolution. Rapid cultural adaptation also leads to persistent differences between local social groups, and then competition between groups leads to the spread of behaviours that enhance their competitive ability. Then, in such culturally evolved cooperative social environments, natural selection within groups favoured genes that gave rise to new, more pro-social motives. Moral systems enforced by systems of sanctions and rewards increased the reproductive success of individuals who functioned well in such environments, and this in turn led to the evolution of other regarding motives like empathy and social emotions like shame.     

Neural substrates of processing syntax and semantics in music

Growing evidence indicates that syntax and semantics are basic aspects of music. After the onset of a chord, initial music-syntactic processing can be observed at about 150-400 ms and processing of musical semantics at about 300-500 ms. Processing of musical syntax activates inferior frontolateral cortex, ventrolateral premotor cortex and presumably the anterior part of the superior temporal gyrus. These brain structures have been implicated in sequencing of complex auditory information, identification of structural relationships, and serial prediction. Processing of musical semantics appears to activate posterior temporal regions. The processes and brain structures involved in the perception of syntax and semantics in music have considerable overlap with those involved in language perception, underlining intimate links between music and language in the human brain.     

Synchrony as an Adaptive Mechanism for Large‐Scale Human Social Bonding

Humans have developed a number of specific mechanisms that allow us to maintain much larger social networks than would be expected given our brain size. For our primate cousins, social bonding is primarily supported using grooming, and the bonding effect this produces is primarily mechanistically underpinned by the release of endorphins (although other neurohormones are also likely to be involved). Given large group sizes and time budgeting constraints, grooming is not viable as the primary social bonding mechanism in humans. Instead, during our evolutionary history, we developed other behaviours that helped us to feel connected to our social communities. Here, we propose that synchrony might act as direct means to encourage group cohesion by causing the release of neurohormones that influence social bonding. By acting on ancient neurochemical bonding mechanisms, synchrony can act as a primal and direct social bonding agent, and this might explain its recurrence throughout diverse human cultures and contexts (e.g. dance, prayer, marching, music‐making). Recent evidence supports the theory that endorphins are released during synchronised human activities, including sport, but particularly during musical interaction. Thus, synchrony‐based activities are likely to have developed due to the fact that they allow the release of these hormones in large‐scale human communities, providing an alternative to social bonding mechanisms such as grooming.     

Social learning and evolution: the cultural intelligence hypothesis

If social learning is more efficient than independent individual exploration, animals should learn vital cultural skills exclusively, and routine skills faster, through social learning, provided they actually use social learning preferentially. Animals with opportunities for social learning indeed do so. Moreover, more frequent opportunities for social learning should boost an individual's repertoire of learned skills. This prediction is confirmed by comparisons among wild great ape populations and by social deprivation and enculturation experiments. These findings shaped the cultural intelligence hypothesis, which complements the traditional benefit hypotheses for the evolution of intelligence by specifying the conditions in which these benefits can be reaped. The evolutionary version of the hypothesis argues that species with frequent opportunities for social learning should more readily respond to selection for a greater number of learned skills. Because improved social learning also improves asocial learning, the hypothesis predicts a positive interspecific correlation between social-learning performance and individual learning ability. Variation among primates supports this prediction. The hypothesis also predicts that more heavily cultural species should be more intelligent. Preliminary tests involving birds and mammals support this prediction too. The cultural intelligence hypothesis can also account for the unusual cognitive abilities of humans, as well as our unique mechanisms of skill transfer.     

Without it no music: cognition,biology and evolution of musicality

Musicality can be defined as a natural, spontaneously developing trait based on and constrained by biology and cognition. Music, by contrast, can be defined as a social and cultural construct based on that very musicality. One critical challenge is to delineate the constituent elements of musicality. What biological and cognitive mechanisms are essential for perceiving, appreciating and making music? Progress in understanding the evolution of music cognition depends upon adequate characterization of the constituent mechanisms of musicality and the extent to which they are present in non-human species. We argue for the importance of identifying these mechanisms and delineating their functions and developmental course, as well as suggesting effective means of studying them in human and non-human animals. It is virtually impossible to underpin the evolutionary role of musicality as a whole, but a multicomponent perspective on musicality that emphasizes its constituent capacities, development and neural cognitive specificity is an excellent starting point for a research programme aimed at illuminating the origins and evolution of musical behaviour as an autonomous trait.     

The structure of cross-cultural musical diversity

Human cultural traits, such as languages, musics, rituals and material objects, vary widely across cultures. However, the majority of comparative analyses of human cultural diversity focus on between-culture variation without consideration for within-culture variation. In contrast, biological approaches to genetic diversity, such as the analysis of molecular variance (AMOVA) framework, partition genetic diversity into both within- and between-population components. We attempt here for the first time to quantify both components of cultural diversity by applying the AMOVA model to music. By employing this approach with 421 traditional songs from 16 Austronesian-speaking populations, we show that the vast majority of musical variability is due to differences within populations rather than differences between. This demonstrates a striking parallel to the structure of genetic diversity in humans. A neighbour-net analysis of pairwise population musical divergence shows a large amount of reticulation, indicating the pervasive occurrence of borrowing and/or convergent evolution of musical features across populations.     

Effects of culture on musical pitch perception

The strong association between music and speech has been supported by recent research focusing on musicians' superior abilities in second language learning and neural encoding of foreign speech sounds. However, evidence for a double association--the influence of linguistic background on music pitch processing and disorders--remains elusive. Because languages differ in their usage of elements (e.g., pitch) that are also essential for music, a unique opportunity for examining such language-to-music associations comes from a cross-cultural (linguistic) comparison of congenital amusia, a neurogenetic disorder affecting the music (pitch and rhythm) processing of about 5% of the Western population. In the present study, two populations (Hong Kong and Canada) were compared. One spoke a tone language in which differences in voice pitch correspond to differences in word meaning (in Hong Kong Cantonese, /si/ means 'teacher' and 'to try' when spoken in a high and mid pitch pattern, respectively). Using the On-line Identification Test of Congenital Amusia, we found Cantonese speakers as a group tend to show enhanced pitch perception ability compared to speakers of Canadian French and English (non-tone languages). This enhanced ability occurs in the absence of differences in rhythmic perception and persists even after relevant factors such as musical background and age were controlled. Following a common definition of amusia (5% of the population), we found Hong Kong pitch amusics also show enhanced pitch abilities relative to their Canadian counterparts. These findings not only provide critical evidence for a double association of music and speech, but also argue for the reconceptualization of communicative disorders within a cultural framework. Along with recent studies documenting cultural differences in visual perception, our auditory evidence challenges the common assumption of universality of basic mental processes and speaks to the domain generality of culture-to-perception influences.     

Intergroup Aggression in Chimpanzees and War in Nomadic Hunter-Gatherers

Chimpanzee and hunter-gatherer intergroup aggression differ in important ways, including humans having the ability to form peaceful relationships and alliances among groups. This paper nevertheless evaluates the hypothesis that intergroup aggression evolved according to the same functional principles in the two species—selection favoring a tendency to kill members of neighboring groups when killing could be carried out safely. According to this idea chimpanzees and humans are equally risk-averse when fighting. When self-sacrificial war practices are found in humans, therefore, they result from cultural systems of reward, punishment, and coercion rather than evolved adaptations to greater risk-taking. To test this “chimpanzee model,” we review intergroup fighting in chimpanzees and nomadic hunter-gatherers living with other nomadic hunter-gatherers as neighbors. Whether humans have evolved specific psychological adaptations for war is unknown, but current evidence suggests that the chimpanzee model is an appropriate starting point for analyzing the biological and cultural evolution of warfare.     

Precursors of Dancing and Singing to Music in Three- to Four-Months-Old Infants

Dancing and singing to music involve auditory-motor coordination and have been essential to our human culture since ancient times. Although scholars have been trying to understand the evolutionary and developmental origin of music, early human developmental manifestations of auditory-motor interactions in music have not been fully investigated. Here we report limb movements and vocalizations in three- to four-months-old infants while they listened to music and were in silence. In the group analysis, we found no significant increase in the amount of movement or in the relative power spectrum density around the musical tempo in the music condition compared to the silent condition. Intriguingly, however, there were two infants who demonstrated striking increases in the rhythmic movements via kicking or arm-waving around the musical tempo during listening to music. Monte-Carlo statistics with phase-randomized surrogate data revealed that the limb movements of these individuals were significantly synchronized to the musical beat. Moreover, we found a clear increase in the formant variability of vocalizations in the group during music perception. These results suggest that infants at this age are already primed with their bodies to interact with music via limb movements and vocalizations.