The origins of music in auditory scene analysis and the roles of evolution and culture in musical creation

Whether music was an evolutionary adaptation that conferred survival advantages or a cultural creation has generated much debate. Consistent with an evolutionary hypothesis, music is unique to humans, emerges early in development and is universal across societies. However, the adaptive benefit of music is far from obvious. Music is highly flexible, generative and changes rapidly over time, consistent with a cultural creation hypothesis. In this paper, it is proposed that much of musical pitch and timing structure adapted to preexisting features of auditory processing that evolved for auditory scene analysis (ASA). Thus, music may have emerged initially as a cultural creation made possible by preexisting adaptations for ASA. However, some aspects of music, such as its emotional and social power, may have subsequently proved beneficial for survival and led to adaptations that enhanced musical behaviour. Ontogenetic and phylogenetic evidence is considered in this regard. In particular, enhanced auditory–motor pathways in humans that enable movement entrainment to music and consequent increases in social cohesion, and pathways enabling music to affect reward centres in the brain should be investigated as possible musical adaptations. It is concluded that the origins of music are complex and probably involved exaptation, cultural creation and evolutionary adaptation.     

Diversity, biology and evolution of IncQ-family plasmids

Plasmids of IncQ-family are distinguished by having a unique strand-displacement mechanism of replication that is capable of functioning in a wide variety of bacterial hosts. In addition, these plasmids are highly mobilizable and therefore very promiscuous. Common features of the replicons have been used to identify IncQ-family plasmids in DNA sequence databases and in this way several unstudied plasmids have been compared to more well-studied IncQ plasmids. We propose that IncQ plasmids can be divided into four subgroups based on a number of mutually supportive criteria. The most important of these are the amino acid sequences of their three essential replication proteins and the observation that the replicon of each subgroup has become fused to four different lineages of mobilization genes. This review of IncQ-family plasmid diversity has highlighted several events in the evolution of these plasmids and raised several questions for further research.     

Challenging the classical notion of time in cognition: a quantum perspective

All mental representations change with time. A baseline intuition is that mental representations have specific values at different time points, which may be more or less accessible, depending on noise, forgetting processes, etc. We present a radical alternative, motivated by recent research using the mathematics from quantum theory for cognitive modelling. Such cognitive models raise the possibility that certain possibilities or events may be incompatible, so that perfect knowledge of one necessitates uncertainty for the others. In the context of time-dependence, in physics, this issue is explored with the so-called temporal Bell (TB) or Leggett–Garg inequalities. We consider in detail the theoretical and empirical challenges involved in exploring the TB inequalities in the context of cognitive systems. One interesting conclusion is that we believe the study of the TB inequalities to be empirically more constrained in psychology than in physics. Specifically, we show how the TB inequalities, as applied to cognitive systems, can be derived from two simple assumptions: cognitive realism and cognitive completeness. We discuss possible implications of putative violations of the TB inequalities for cognitive models and our understanding of time in cognition in general. Overall, this paper provides a surprising, novel direction in relation to how time should be conceptualized in cognition.     

Harmonic medicine: the influence of music over mind and medical practice

The Yale Medical Orchestra displayed exceptional talent and inspiration as it performed a timeless composition to celebrate Yale School of Medicine's bicentennial anniversary during a December 2010 concert. Under the leadership of musical directors Robert Smith and Adrian Slywotzky, the richly emotional meditations of Mendelssohn, Dvorak, Schubert, and Yale's own Thomas C. Duffy filled the minds and hearts of an audience as diverse as the orchestra. I intend to retrace the steps of that melodic journey in this essay, fully aware of the limits imposed on me to recreate the aural art form through the medium of text. While these symbols can be pale representations of the beauty and complexity of the music, I hope they will be the building blocks for the emotional experience of the audience. I describe the works' inception and their salient musical features and then review what we know about the effects of melody, meter, and timbre on our brains. My intentions are to provide evidence to encourage the further use of music as a tool in medical practice, provide interest in the works explored by the Yale orchestra, support the orchestra itself, and investigate a personal passion.     

Harmonic calls and indifferent females: no preference for human consonance in an anuran

The human music faculty might have evolved from rudimentary components that occur in non-human animals. The evolutionary history of these rudimentary perceptual features is not well understood and rarely extends beyond a consideration of vertebrates that possess a cochlea. One such antecedent is a preferential response to what humans perceive as consonant harmonic sounds, which are common in many animal vocal repertoires. We tested the phonotactic response of female túngara frogs (Physalaemus pustulosus) to variations in the frequency ratios of their harmonically structured mating call to determine whether frequency ratio influences attraction to acoustic stimuli in this vertebrate that lacks a cochlea. We found that the ratio of frequencies present in acoustic stimuli did not influence female response. Instead, the amount of inner ear stimulation predicted female preference behaviour. We conclude that the harmonic relationships that characterize the vocalizations of these frogs did not evolve in response to a preference for frequency intervals with low-integer ratios. Instead, the presence of harmonics in their mating call, and perhaps in the vocalizations of many other animals, is more likely due to the biomechanics of sound production rather than any preference for ‘more musical’ sounds.     

Auditory perception and the evolution of speech

Among topics related to the evolution of language, the evolution of speech is particularly fascinating. Early theorists believed that it was the ability to produce articulate speech that set the stage for the evolution of the «special» speech processing abilities that exist in modern-day humans. Prior to the evolution of speech production, speech processing abilities were presumed not to exist. The data reviewed here support a different view. Two lines of evidence, one from young human infants and the other from infrahuman species, neither of whom can produce articulate speech, show that in the absence of speech production capabilities, the perception of speech sounds is robust and sophisticated. Human infants and non-human animals evidence auditory perceptual categories that conform to those defined by the phonetic categories of language. These findings suggest the possibility that in evolutionary history the ability to perceive rudimentary speech categories preceded the ability to produce articulate speech. This in turn suggests that it may be audition that structured, at least initially, the formation of phonetic categories.     

Extractive foraging and the evolution of primate intelligence

One of the two major theories regarding the evolution of intelligence in primates is that feeding strategies determine mental development. Evidence for this theory is reviewed and related to extractive foraging, which is the act of locating and/or processing embedded foods such as underground roots and insects or hard-shelled nuts and fruits. It is shown that, although only cebus monkeys and chimpanzees in the wild use tools in extractive foraging, many other species of mammals (including primates) and birds are capable of extracting embedded foods without tools. Extractive foraging by primates is compared to extractive foraging by other mammals and birds to assess whether: 1) extractive foraging involves cognition, and 2) extractive foraging by primates is unique in a way that may mean it played a role in the development of intelligence among primates. This comparison reveals that some acts of extractive foraging by nonprimates are equally sophisticated as those of primates. It is suggested that extractive foraging played no significant role in the evolution of primate intelligence. Hypotheses for testing precise differences in extractive foraging ability across taxa are offered, and the roles of olfactory cues, manual dexterity, and strength in extractive foraging are evaluated. In conclusion, the hominization process is briefly reviewed in relation to foraging behavior. A ?package? of traits that, in combination, is unique to hominids is discussed: tool-aided extractive foraging, division of labor by sex with food exchange, and feeding of juveniles.     

Social cognition and psychopathology: a critical overview

The philosophical and interdisciplinary debate about the nature of social cognition, and the processes involved, has important implications for psychiatry. On one account, mindreading depends on making theoretical inferences about another person''s mental states based on knowledge of folk psychology, the so-called “theory theory” (TT). On a different account, “simulation theory” (ST), mindreading depends on simulating the other''s mental states within one''s own mental or motor system. A third approach, “interaction theory” (IT), looks to embodied processes (involving movement, gesture, facial expression, vocal intonation, etc.) and the dynamics of intersubjective interactions (joint attention, joint action, and processes not confined to an individual system) in highly contextualized situations to explain social cognition, and disruptions of these processes in some psychopathological conditions. In this paper, we present a brief summary of these three theoretical frameworks (TT, ST, IT). We then focus on impaired social abilities in autism and schizophrenia from the perspective of the three approaches. We discuss the limitations of such approaches in the scientific studies of these and other pathologies, and we close with a short reflection on the future of the field. In this regard we argue that, to the extent that TT, ST and IT offer explanations that capture different (limited) aspects of social cognition, a pluralist approach might be best.     

Contemporary evolution meets conservation biology II: impediments to integration and application

Conservation biology needs to be concerned not just with exogenous threats to populations, but also with the changing nature of populations themselves. In a previous review paper, we highlighted evolution in contemporary time (years to decades) as a largely overlooked aspect of population responses to environmental perturbations. We argued that these responses might affect the fate of natural, managed and exotic populations. In the present review, we discuss issues that may limit the integration of contemporary evolution into conservation biology—with the intent that recognition of these limitations may foster research, discussion and resolution. In particular, we consider (1) alternative perceptions of “evolutionary” and “ecological” time, (2) the role of contemporary evolution as an ecological process, (3) fitness as a bridge between evolution and conservation, and (4) challenges faced by conservation strategies based on gene flow estimation or manipulation. We close by highlighting some situations in which current conservation approaches and contemporary evolution may require reconciliation.     

A gray matter of taste: Sound perception, music cognition, and Baumgarten's aesthetics

Music is an ancient and ubiquitous form of human expression. One important component for which music is sought after is its aesthetic value, whose appreciation has typically been associated with largely learned, culturally determined factors, such as education, exposure, and social pressure. However, neuroscientific evidence shows that the aesthetic response to music is often associated with automatic, physically- and biologically-grounded events, such as shivers, chills, increased heart rate, and motor synchronization, suggesting the existence of an underlying biological platform upon which contextual factors may act. Drawing on philosophical notions and neuroscientific evidence, I argue that, although there is no denying that social and cultural context play a substantial role in shaping the aesthetic response to music, these act upon largely universal, biological mechanisms involved with neural processing. I propose that the simultaneous presence of culturally-influenced and biologically-determined contributions to the aesthetic response to music epitomizes Baumgarten's equation of sensory perception with taste. Taking the argument one step further, I suggest that the heavily embodied aesthetic response to music bridges the cleavage between the two discrepant meanings-the one referring to sensory perception, the other referring to judgments of taste-traditionally attributed to the word "aesthetics" in the sciences and the humanities.     

Systems biology of evolution: the involvement of metal ions

This article outlines a novel way of looking at the relevance of metal ions in organisms to the whole of life as part of an ecosystem bringing together the environment and cellular life. It does so by examining the evolution of the environment due to the “waste”, mainly oxygen, from cell metabolism which back reacts with the cells themselves. The oxygen generates a progressive change in the metal ions in the environment. The resultant change is buffered by ferrous iron and sulfide and is therefore slow so that there is a gradual adaptation of life to utilisation of elements in a time sequence. In order to appreciate this, systems (biological) evolution, it is necessary to describe the very nature of a thermodynamic flow system of which life is an example.     

Immediate physiological responses of healthy volunteers to different types of music: cardiovascular, hormonal and mental changes

A group of 20 healthy volunteers [10 women, 10 men; median age 25 (20–33) years] were examined by means of pulsed wave Doppler echocardiography, blood sample analysis and psychological testing before and after listening to three different examples of music: a waltz by J. Strauss, a modern classic by H. W. Henze, and meditative music by R. Shankar. To assess small haemodynamic changes, mitral flow, which reflects left ventricular diastolic behaviour, was measured by Doppler ultrasound. Heart rate, arterial blood pressure and plasma concentrations of adrenocorticotropic hormone, cortisol, prolactin, adrenaline, noradrenaline, atrial natriuretic peptide (ANP) and tissue plasminogen activator (t-PA) were determined simultaneously. Transmitral flow profile is characterized by early E-wave and late atrial induced A-wave. Velocity-time integrals were measured and the atrial filling fraction was calculated. The mental state was measured by using a psychological score (Zerssen) with low values (minimum 0) for enthusiastic and high values (maximum 56) for depressive patterns. Music by J. Strauss resulted in an increase of atrial filling fraction (AFF; 29% vs 26%;P<0.05) and ANP (63 pg·ml^–1 vs 60 pg·ml^–1;P<0.05). The mental state was improved (Zerssen: 6.5 vs 11 points;P<0.05). After the music of H. W. Henze prolactin values were lowered (7.7 ng·ml^–1 vs 9.1 ng·ml^–1;P<0.01). The music of R. Shankar led to a decrease of cortisol concentrations (57 ng·ml^–1 vs 65 ng·ml^–1;P<0.001), noradrenaline concentrations (209 g·l^–1 vs 256 g·l^–1;P<0.01) andt-PAantigen concentrations (1.1 ng·ml^–1 vs 1.4 ng·ml^–1;P<0.05). Heart rate and blood pressure remained unchanged during the whole experiment. We concluded that different types of music induced changes of left ventricular diastolic function and plasma hormone concentrations. After rhythmic music (Strauss) AFF and ANP increased significantly, the mental state being improved. Meditative music (Shankar) lowered plasma cortisol, noradrenaline and t-PA concentrations; the observed increase of early left ventricular filling was not statistically significant. Prolactin concentrations decreased after modern music (Henze). Thus, it would seem to be possible to detect cardiovascular changes following different types of music by Doppler ultrasound and hormone analysis, meditative music having promising therapeutic implications in the treatment of conditions of stress.This paper contains data from J. Vollert's work for his doctoral degree.     

Hantavirus evolution in relation to its rodent and insectivore hosts: no evidence for codivergence

Hantaviruses are considered one of the best examples of a long-termassociation between RNA viruses and their hosts. Based on theappearance of strong host specificity, it has been suggestedthat hantaviruses cospeciated with the rodents and insectivoresthey infect since these mammals last shared a common ancestor,approximately 100 million years ago. We tested this hypothesisof host–virus codivergence in two ways: 1) we used cophylogeneticreconciliation analysis to assess the fit of the virus treeonto that of the host and 2) we estimated the evolutionary ratesand divergence times for the Hantavirus genus using a BayesianMarkov Chain Monte Carlo method and similarly compared thesewith those of their hosts. Our reconciliation analysis providedno evidence for a history of codivergence between hantavirusesand their hosts. Further, the divergence times for the Hantavirusgenus were many orders of magnitude too recent to correspondwith the timescale of their hosts' speciation. We thereforepropose that apparent similarities between the phylogenies ofhantaviruses and their mammalian hosts are the result of a morerecent history of preferential host switching and local adaptation.Based on the presence of clade-defining amino acids in all genomicsegments, we propose that the patterns of amino acid replacementin these viruses are also compatible with a history of host-specificadaptation.     

Correlations in the population structure of music,genes and language

We present, to our knowledge, the first quantitative evidence that music and genes may have coevolved by demonstrating significant correlations between traditional group-level folk songs and mitochondrial DNA variation among nine indigenous populations of Taiwan. These correlations were of comparable magnitude to those between language and genes for the same populations, although music and language were not significantly correlated with one another. An examination of population structure for genetics showed stronger parallels to music than to language. Overall, the results suggest that music might have a sufficient time-depth to retrace ancient population movements and, additionally, that it might be capturing different aspects of population history than language. Music may therefore have the potential to serve as a novel marker of human migrations to complement genes, language and other markers.     

Cranial morphology and development: new light on the evolution of language

A hypothesis is presented which may explain within a single framework both the large behavioural differences and the large differences in head morphology between the great apes and humans. All these differences can be parsimoniously explained by a shift of few regulatory genes controlling the onset of the division of late migrating neurons in the human cortex. This simple shift resulted in the following effects: 1) the neurocranium responded to brain enlargement by increasing mineral deposition on its external surface, increasing its overall size and mass. 2) This increase in the braincase was largely achieved by developmental reabsoption of the face bones. 3) The relative shift in growth between these two skull components also induced a rearrangement at the basicranium level. This brought about the facial orthognatism of modernHomo and, as a mechanical by-product, the descent of the larynx into the throat. Brain enlargement led to a large increase in cognitive capacity, and as a developmental byproduct, produced a mechanical organ preadapted for speech, as well as bringing about the reduction of canines and the origin of the chin. In this study, the phylogenetic basis, the selective pressures, and the behavioural consequences of this process during hominization are examined. Cognitiveversus communicative aspects of human language are distinguished and discussed. Cognitive capacities were the first to be selected due to the survival advantage of mapping huge territories during the expansion of the Plio-Pleistocene savanna ecotone. The present hypothesis is then compared with current theories leading to the conclusion that it is a more parsimonious explanation. It integrates data from a wide array of fields of human biology, pathology and clinical medicine, all assessed from evolutionary and ecological perspectives.