|Music and Human Evolution|
By Alan R Harvey
“The senseless happiness of music engulfed me like a golden bath; it’s a happiness that never depends on the objective, only the subjective, and perhaps it has a more profound link with the humanness of things because it’s altogether senseless: the strenuous production of certain nonsensical sounds – that are no good for anything – for no explicable reasonable purpose”.
Josef Skvorecky, The Bass Saxophone1.
It is often said that there is no culture, no group of humans across the planet that lacks music, lacks dance. Music is a universal that can profoundly affect people as individuals and influences their interactions within others. Its impact is mysterious because music is not usually propositional, it does not put forward any testable hypotheses, and it promulgates no doctrines and preaches no gospels2. It has no immediate or evident efficacy, neither ploughs, sows, weaves or feeds3. According to the philosopher Schopenhauer music is “a copy of the will itself, music speaks of essence, the inner spirit”4. So what is music, why do humans make music and respond to it, why is it such an important part of our lives? And, equally importantly, how does music relate to language? From an evolutionary point of view did music come before language, did language come before music – or was there some common progenitor that somehow separated into two strands when homo sapiens evolved, with both strands of communication retained – and if so, WHY were both retained?
Of course most of us are aware of what music does to us – for thousands of years the famous and wise have left many opinions on the subject. According to Confucius, “Music produces a kind of pleasure which human nature cannot do without”, and Aristotle pondered, “Why do rhythms and melodies which are mere sounds resemble dispositions, while tastes do not, nor yet colours or smells?” The Oxford English Dictionary has something a little bit drier. “Music – that one of the fine arts which is concerned with the combination of sounds with a view to beauty of form and the expression of emotions”. The composer Paul Hindemith made this interesting comment: “Music… is meaningless noise unless it touches a receptive mind”5. I suggest this could be modified slightly to: “Music is meaningless noise unless it touches a receptive human mind”. In this, perhaps controversial definition, whale “song”, bird “song”, gibbon “song” etc represent subtle and complex modes of communication, but they are not music. Music clearly affects our arousal, affects our emotional and physiological responses, it is intimately linked to movement and dance. Music structures time, provides mnemonic frameworks that help memory and organise knowledge, it is a glue that promotes collective expression and experience of emotion, helps provide cohesion and organisation to our social architecture. It forms a core component of ceremony and ritual. Music is, to quote Anthony Storr, “a permanent part of our mental furniture”2.
Music has so-called prosodic information, emotional information – there are pitch changes, tonal relationships, melody and harmony, changes in volume, metre and rhythm, changes in emphasis. Language has syntax and grammar, it is symbolic, it is generative, it is referential, and it allows intuitive reasoning. For many, its creation must have been closely linked to the evolution of consciousness. To quote Rod Mengham from his book On Language, “Without language with tenses that determine the differences between past, present and future, and without the means of defining the limits of personal agency, one cannot relate phenomena through time and in space”6. But music and language are not entirely distinct from each other. No language is in a monotone, there are pitch and rhythmic changes, and in many languages the nature of the pitch changes, or whether the pitch is high or low, can completely alter the meaning of a particular word or phrase.
Another way of addressing the relationship between music and language is to look at the brain and work out which regions and neural networks are associated with these two communication systems. Are they separate or do they share common features? There are in fact many examples in the neurological literature of dissociative loss of musical abilities (amusia) but not language, and visa versa (see also examples in the recent book by Oliver Sacks – Musicophilia) 7. Modern imaging techniques such as functional Magnetic Resonance Imaging (fMRI) allow researchers to monitor brain activity while subjects perform or think about specific tasks. But studying how the brain processes music is complex because it can be difficult to isolate specific characteristics – acoustic input and analysis, pitch, intervals and melodies, timbre, processing of rhythm and metre, memory processing, and of course there is emotional expression/responsiveness. There is also the motor side – singing, humming, tapping of hands or feet, playing of different types of musical instrument8. And analysis of language can be just as complex.
Despite these difficulties, numerous brain imaging studies have shown that there are areas in the brain that are clearly activated during processing of music. Other studies have examined which areas are most activated when performing language-specific tasks. Overall, while language seems to be predominantly processed in the left cerebral hemisphere, and perhaps rhythm as well, analysis of harmony and melodies, timbre, pitch comparison and retention etc appears to involve systems in the right hemisphere, often in the temporal lobe (FIG. 1). Interestingly, most studies have found that musical training/experience alters the pattern of activation, there being a general shift towards increased processing in the left hemisphere. The imaging work confirms neurological reports and shows the presence of specific music processing networks in the brain of homo sapiens. But some shared networks also exist; for example there is overlap in the regions involved in melody and sentence generation9, and there is evidence that musical syntax is processed in Broca’s area, an area normally associated with generation of speech (FIG. 1). “We find that these areas are also responsible for an analysis of incoming harmonic sequences, indicating that these regions process syntactic information that is less language-specific than previously believed”10.
The foregoing observations point to divergent but also some shared networks that subserve music and language. From a developmental point of view, Koelsch and Siebel11 have suggested that “the human brain at least at an early age, does not treat language and music as strictly separate domains, but rather treats language as a special case of music”. If language evolved or piggy-backed on circuitries that previously performed different functional roles, some overlap in the processing streams might be expected, especially if both types of communication evolved from a common protolanguage. The idea of a protolanguage or musilanguage12 in our forbears has been around for a while, at least since Darwin. Our ancestors and cousins, whoever they were, must have had very complex communication skills. Steve Mithen in his book The Singing Neanderthals has coined a term for this presumed communication: ‘Hmmmm’, which stands for holistic, manipulative, multimodal, musical, mimetic13.
Mimesis is a behaviour that rests on the ability to produce conscious self initiated representational acts that are intentional but not linguistic14. They are defined primarily in terms of their representational function such as putting your hand across your heart or covering your face to say you're sad or embarrassed. Modern language seems to be built on this type of foundation. In this context it is intriguing that there are suggested links between manual gestures and language15, and the major motor speech area (called Broca’s area) has been shown to be also involved in complex hand movements16. No wonder sign language works so well.
Richard Dawkins (Unweaving the Rainbow)17 suggests that language may have been the spark that began the self-reinforcing, rapid evolution of homo sapiens. Dawkins talks about a self-feeding event where there was some co-evolution or co-adaptation of a software change and a hardware change that suddenly projected everything forward: “a social world in which there is language is a completely different kind of social world… the selection pressures on genes will never be the same again”. In some ways this idea is not that much different from Vilayanur Ramachandran’s suggestion in his book The Emerging Mind18 that “it is the fortuitous synergistic combination of a number of mechanisms which evolved for other purposes initially that later became assimilated into the mechanism that we call language”. The result, as described by Merlin Donald at the end of his book Origins of the Modern Mind is that “if we compare the complex representational architecture of the modern mind with that of the ape, we must conclude that the Darwinian universe is too small to contain humanity. We are a different order”14. Because of language, the ability to embody and symbolise information, to use generational/abstract thought, the capacity to handover data and knowledge of life’s experiences to the next generation, we rapidly moved on – culture began to drive evolution.
We do not know anything about the hardware or software of our immediate ancestors or our recent cousins the Neanderthals. Measurements of brain size and the presumed size of individual components give us only a very small amount of information. It seems likely that gene expression in our close relatives was very similar to modern-day homo sapiens but that there was some change, some co-evolution or adaptation of several small mutations, that provided the crucial cognitive tipping point. Changes could have occurred that influenced brain size, or more likely the relative size of particular components within the brain, changes could have altered the neural circuitry between regions of the brain, or perhaps there were changes in the molecular basis of synaptic plasticity (the connections between nerve cells) that as a consequence altered our learning abilities and memory storage capacity.
Remarkably, such small changes (polymorphisms) in the sequences of certain proteins have been identified in the modern human population and linked to memory performance and speech capabilities. The brain shows the most changes in gene expression, at least 2% of expressed sequences are differentially expressed in human cortex compared with chimps19. Gilad et al20, using expression profiling of genes describe a rapid evolution of human transcription factors compared with primates, most differences seem to be due to gene regulation – how one gene regulates the signalling of another. Thus modern humans have a much more active or dynamic brain environment, a more complex and more subtle transcription profile. Even more remarkably, a recent study describes polymorphisms in two neuromodulator-related genes that seem to be associated with creative dance performance, with the emotional side of dance 21. Nonetheless, genes may not have been the whole story; as Ramachandran has suggested18, some additional cross-wiring may have emerged between existing brain regions, facilitating cross-modal processing. WH Calvin suggests we already had a core facility for stringing things together, and language evolved from, or was superimposed upon, that basic facility22.
When did this explosion happen, when did modern humans, language, sentience – when did it all begin? There is evidence of anatomically modern humans at about 150,000-200,000 years ago in southeast Africa and evidence of these humans in the middle-east 100,000 years ago although I suspect that although they were modern skeletally they were not modern in terms of brains, that I believe came a little later. Certainly by 50,000 years ago there were modern humans in Australia, and they had language and music. Examination of the variability of sequences of genes on the Y chromosome, which is carried by men and not women, suggests there was a founder population that gave rise to all modern humans perhaps 60,000-80,000 years ago23, 24. These data remain controversial, but we may well be that young; some estimates of the size of that founder population are as low as 2,000-6,000 members.
There must have been some selection, perhaps related to some minor genetic change, some behavioural change that gave us an advantage and from that time we rapidly evolved, only tens of thousands of years ago. What might have provided the impetus for that change? There was a massive volcanic eruption on the Island of Toba in Indonesia just over 70,000 years ago. This was a major catastrophe – a volcanic winter – that cooled the world, and was perhaps a trigger that initiated the most recent Ice Age. There are some who believe that this world-changing event was the so-called bottle neck through which the new human species passed, but other homo varieties did not25. Homo sapiens must have had some special attributes – including presumably speech, sophisticated communication and a higher representational cognitive architecture – that gave us a selective advantage and allowed us to survive this environmental wipe-out.
But what about music – when do we first see evidence of musicality in homo sapiens? A piece of thigh bone that may have had holes drilled into it to make a flute was found in an Eastern European cave (FIG. 2). It has been dated at about 40,000-45,000 years and has been described as being Neanderthal26. But even if it is a flute, Neanderthals and homo sapiens co-existed for a period of time and it is possible this cave site was taken over by modern humans and that they left the artifact behind… such are the imponderables of archaeology. Overall however, Neanderthals seem to have been in relative cognitive/cultural stasis for many hundreds of thousands of years – they clearly lacked the blue touch paper that appeared in a small African group that rapidly came to dominate the global hominid landscape.
So to return to the original question, if our immediate ancestors possessed a protolanguage or musilanguage, why do we – homo sapiens – perhaps uniquely amongst any species, have two separate types of communication, essentially running in parallel? Why retain music and all of its associations? Is it merely a cursory pleasure or is there some deeper evolutionary subtext? Robin Dunbar has interesting theories about the evolution of language – and as he points out if you are talking to someone, once you get more than about four people it becomes difficult to communicate with all of them27. Music on the other hand allows large group participation in which you can contribute as an individual but in addition the individual is physiologically linked into the larger network, the arousal patterns become yoked together – there is a sense of oneness, a sense of community. Others including Steven Brown12 also discuss the importance of music at the level of the group – increased cooperative survival strategies, group identity, collective thinking, group catharsis, collective expression and experience of emotion – these all seem to have been important during the evolution of ‘us’ as we became self-aware, as we developed language. This prosodic, emotional mode of communication seems critical to our psychological well-being.
David Huron has summarised other potential benefits of music28: there is mate selection (a favourite of Charles Darwin), group effort, perceptual development, motor skill development, conflict reduction, and there is also of course trans-generational communication (where music and song can be a useful mnemonic device for passing verbal information from one individual to another and, in particular, from one generation to the next). There is also the idea that a type of non-verbal, perhaps musical communication forms the basis of parent-infant bonding. Ellen Dissanayake suggests that music (which she sees as part of a multimedia presentation including dance/mime etc) springs from the need for pre-language interactions between mother and baby29; so-called lalling sounds or crooning. This pre-verbal communication is important to integrate attention, learning and perhaps aid in the development of self-awareness – linking intention with actions of expression and execution. Perhaps the prosodic elements of music have been retained and continue to affect us in adult life. There is much to be said for this idea, although as far as I know there is no obvious sexual dimorphism in terms of music and dance, perhaps one might have expected that Mums might be better at this stuff than Dads if it is assumed that Mums spent more time with their infants?
I have found some new and interesting correlations between musical processing and various human behavioural characteristics (FIG. 3). Using fMRI it has proved possible to demonstrate that, for example, when a subject listens to different sorts of music there are correlations between changes in brain activity in different areas and whether the music has positive or negative subjective attributes30. Some of the areas that are activated by music that is perceived as pleasurable are also activated when people look at erotica31. On the other hand other brain regions, including parts of what is called the limbic system, are activated when listening to sad music32. The limbic system is involved in rage, anger, involved in emotional responsiveness, and in responding to music it here seems to be involved in negative affect. A final and especially intriguing correlation relates to altruistic human behaviour. It is possible to image brain activity in subjects involved in cooperative tasks, for example a prisoner game where subjects make choices on whether to be nice or nasty to another prisoner33. If you make altruistic choices, which put the other prisoner’s welfare first, this cooperative behaviour is associated with activation of brain areas that have been linked with reward processing: “We propose that activation of the neural network possibly reinforces reciprocal altruism, thereby motivating subjects to resist the temptation to selfishly accept but not reciprocate favours”34. Some of the areas activated by reward behaviours and socially cooperative acts overlap with areas activated when listening to pleasurable music. In my view this is not coincidental.
What is the relevance of music today and in the future, in terms of the well-being of human kind? There are documented transferable benefits of music training such as improvement in visuospatial skills35 and there is considerable evidence, albeit much of it anecdotal, that music has therapeutic power. This is has been divined for centuries – “Black care shall be lessened by sweet song” – so said Horace in 24BC. In this context it is vitally important to put music and its physiological and behavioural effects on homo sapiens onto a sure scientific footing, to determine exactly where it is processed in the brain, to understand how it has its impact, and then to understand – as the ancients did – that music has clear relevance to medicine and to mental health7. Why for example do neurologists, psychiatrists and clinical psychologists not use music as part of their diagnostic armamentarium – to examine mood and emotional responsiveness in patients? There are numerous studies on musical therapy and the beneficial impact that it has on, for example, pre-term infants, children, and those older persons with various neurodegenerative disorders such as Alzheimers and Parkinsons disease. Menon and Levitin proposed that music offers a “simple and elegant way to probe the neural basis of anhedonia (loss of pleasure in daily activities) in a number of psychiatric disorders, including depression, schizophrenia, and bipolar disorder”36. Music associated physical therapy improves gross motor and fine motor function, coordination and rehabilitation. After stroke there are reports that musically assisted speech can aid in the treatment of non fluent aphasia, a disorder sometimes encountered following cerebral vascular injury.
The more we study music and its place in the evolution of the modern mind, why we have retained this form of communication in parallel to language, complementary but distinct, the more we will discern clues that may help put music back into the forefront of scientific and philosophical thought. We will discover more situations where neurologists and therapists will be ready to accept a scientific rationale for the healing power of music, we will generate more cogent arguments about why music and dance should remain central to our education, should remain central to the human experience. Because if we become isolated from that then there may be very real dangers associated with the breakdown of social structure, our relationships with each other, and our comfortableness with ourselves as we go through life. Anthony Storr in his book Music and the Mind2 eloquently discusses this modern need and with it the importance of music in education, and here I will quote from the introduction to his book. It is worth quoting in full: “Many people assume that the arts are luxuries rather than necessities, and that words or pictures are only the means by which influence can be exerted on the human mind.
Those who do not appreciate music think it has no significance other than providing ephemeral pleasure (and here I think of Steven Pinker in this regard who notoriously called music “auditory cheesecake”). They consider it a gloss upon the surface of life; a harmless indulgence rather than a necessity. This, no doubt, is why our present politicians seldom accord music a prominent place in their plans for education. Today, when education is becoming increasingly utilitarian, directed toward obtaining gainful employment rather than toward enriching personal experience, music is likely to be treated as an ‘extra’ in the school curriculum which only affluent parents can afford, and which need not be provided for pupils who are not obviously ‘musical’ by nature.
But along with the phenomenon of consciousness there comes a potential price… “there is a tragic dimension to consciousness… there is madness, depression, guilt, and dread. There is the fear of death – and strangest of all, the fear of life. For some people, in some circumstances, consciousness becomes so unbearable that they commit suicide to bring it to an end. ‘To be or not to be?’ is a peculiarly human question”37. For whatever reason, suicide rates have gone up in the last thirty years; it is estimated that the rate of suicide in the 15-24 age group has increased from 10:100,000 to 30 per 100,000 during that period38. The rate also increased in the 25-34 age group. Is this related to an increased sense of desperation, isolation, people not believing that they belong, loss of a belief in the gods and an afterlife – is this something that has been a threat to the newly sentient homo sapiens since the beginning? Was it the case that the smarter we got, the lonelier we got?
We needed a de-isolator, something to foster social cohesion, something to physiologically bring us together, to share common states of experience and arousal… was music, and with it dance, a critical part of the glue that helped bind us together? Is this why our founder population survived, in possession of this great gift? Music is in partnership with speech, it is associated with altruism and emotional affect, it has the ability to shape time and perception, and it is a critical part of our mental well-being. It binds us together with others, momentarily we forget our isolation, out mortality, and we forget the sheer brutal highbeam of consciousness that paralyses us, that reminds us that one day we will no longer be. Was this what Nietzsche meant when he said “We possess art lest we perish from the truth”?
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2. Storr, A. (1992) Music and the Mind. HarperCollins.
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4. Schopenhauer, A. Quoted in Storr, Music and the Mind.
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29. Dissanayake, E. (2004) Antecedents of the temporal arts in early mother-infant interaction. In: The Origins of Music, N.L. Wallin, B. Merker, S. Brown (Eds), MIT Press, pp 389-410.
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Alan Harvey is a Professor of Neuroscience at the School of Anatomy and Human Biology, The University of Western Australia. This paper is developed from two talks, one given to the ABC’s Science Show in July 2006, the other the 2007 Callaway Lecture, given at UWA’s School of Music in July 2007.