Language and Evolution: Homepage Robin Allott

The Biological Bases of Music

[Extracts from The Pythagorean Perspective]

INTRODUCTION

Literature, music, mathematics, art, are constituents of culture and each of them has its separate history. But each of them can also be seen as a manifestation of a human biological drive, a drive towards exploration, experimentation, the analysis of human perception. Culture is not something separate from human evolution but a part of a continuing human evolution, indeed the main form which human evolution has taken over the last few thousand years. It is a familiar idea, but perhaps a wrong one, that human evolution, as a Darwinian process, has ceased and been replaced by something quite new, a more Lamarckian process involving the inheritance of acquired characteristics, more specifically of the changing forms of human culture. On this see for example Dawkins (1986), or Huxley(1926).

MUSIC

To attempt an evolutionary account of any one of the arts, the first step is to see what points of contact the particular art has with biology, what are the physiological and neurological foundations of the art, both in production and reception. What are the biological prerequisites, components, or effects? What relevant clinical or scientific evidence is there?

In the case of music, there is a good deal. This section draws on material from a variety of sources of which the most important have been the papers assembled by MacDonald Critchley (an eminent neurologist) in his Music and the Brain (1977) and Terence McLaughlin's Music and Communication (1970).

McLaughlin points out that music conveys the subjective experience of composers - but in what way? Herbert Spencer tried to trace a development of music from speech gestures. Darwin suggested that music preceded and gave rise to speech. But there has been no consensus. "Wherever we turn, the origins of music remain mysterious". One proposal has been the that music should be thought of as 'audible arithmetic'. Leibniz wrote that music is "a hidden arithmetical exercise for the soul". The Pythagoreans observed that the ratios of the lengths of strings, or other vibrating materials, followed simple mathematical relationships with the sounds they produced. Tests by experimental psychologists have shown that the order of preference for chords in most people follows the lines predicted from Pythagorean theory. The relation of music to what might be called 'neural mathematics' is a topic to which I shall return in a later section.

More specific information is available on other physiological aspects of music:

Synaesthesia

The most common musical synaesthetic experience is seeing colours or patterns when music is heard or composed. 'Colour hearing' has been reported as far back as the time of Ptolemy. The British composer, Arthur Bliss, experienced a constant play of colour sensations while he was composing; Rimsky- Korsakov and Scriabin associated different musical keys with different colours. Timbre especially has close colour affinities, see the descriptive use of 'tone-colour' - 'Klangfarbe'. An analogy (even a homoeomorphism) has been seen between the seven colours of the spectrum, with their steadily increasing electromagnetic frequency from red at one end of the spectrum to blue or violet at the other, and the seven notes of the diatonic scale, with their increasing audio-frequency. Newton pointed out the resemblance between the colour scale and the musical scale. Colour-sound synaesthesia can be seen as a demonstration of sympathy between the various sense modes (which we take for granted in the form of metaphor and symbol). Many other types of synaesthesia associated with music have been recorded. Body schema, tactile and kinaesthetic synaesthesias and hallucinations linked to music seem fairly common.(Critchley)

Temporal (rhythmic) effects

Apart from the rhythm of breathing, the other dominant rhythmic sound in our lives is the heartbeat. The rhythms of the heart, lungs, brain and body - the swing of the arms and legs in walking, account for most of the small units of pattern to which we have become accustomed. All give us some sense of the 'natural' tempo: moderate neutral M.M. [metronome mark] 50 to M.M. 95 is felt as 'comfortable'. The duration of 0.75 second seems to be a psychic constant corresponding to the duration of the complete process of perception. The connection of this natural tempo with walking pace and heartbeat is not a coincidence; the brain is controlling all our muscular processes, and it seems natural and economical that for the rhythmic ones, it should select a tempo that is already in use. The other important human reaction to time is to break it up into units or unit patterns, the origin of our sense of rhythm.(McLaughlin)

Motor effects

Music has a direct relation to the nervous organisation of postures and movements. These postures and movements are complex combinations and recombinations of the simplest fixations and movements of individual joints brought about by a few muscles acting at each joint. The whole listening group responds by motor responses, rarely - in public - overt motor activity but rather sensations of movement, a succession of postural adjustments or even foot tapping. Composition, performance and listening imply wide involvement of the cerebral motor cortex, subcortical motor and sensory nuclei and the limbic system (Critchley)

Muscular response differs between cranial muscles and those of the extremities. At rest only minor differences occur between muscular activity in the forehead region and in the legs. While the subject listens to a record of dance music the effect of the music goes, so to speak, 'into the legs'; muscle action potentials increase sharply in the legs and relatively slightly in the frontalis muscles.

Other bodily response

Perceptual and emotional musical experiences lead to changes in blood pressure, pulse rate, respiration, the psycho-galvanic reflex and other autonomic functions. These autonomic changes represent the vegetative reflections of psychological processes. During the act of conducting, the highest pulse frequencies are not reached at moments of greatest physical effort but occur at passages producing the greatest emotional response, passages which the conductor [Karajan] singled out as being the ones he found most profoundly touching. At these moments the pulse rate increased for a short while to twice the level of the initial value.

It is sometimes possible to 'drive' the pulse rate by dynamic changes in volume such as the crescendo and decrescendo of a rolling drum beat. The same phenomenon can be obtained by a change in rhythm acceleration deceleration. sometimes synchronously with the respiratory rhythm. Recordings of respiratory movements during the playing of music are very informative. During performance of a Brandenburg concerto, oscillations of the pulse rate occurred synchronously with the respiration. At the end of the performance the respiratory rate fell to levels which were less than half those at the peak. When a subject is asked to squeeze an ergometer, an instrument which measures the strength of the handgrasp at regular intervals and with equal effort he will be unable to carry out the test properly while music is being played. Lullabies invariably decrease and march songs increase muscular strength.(Harrer) The elements of musical language could also be analysed to see how far their emotional associations correspond to their physical effects. Other bodily reactions [besides pulse, blood pressure, respiration] such as the digestive system, the pelvic reflexes, the skin, and so on, would well repay attention.(McLaughlin)

Neural patterning

There are strong analogies or structural similarities between music and the fundamental operations of the nervous system. The characteristics of nerve impulses - timing, intensity, synchronicity, frequency-contrasts, patterning generally - can be set in parallel with many aspects of musical construction. The fibre tracts of the auditory system are arranged tonotopically so that the frequency organisation of the cochlea is maintained at all levels from the auditory nerve to the cortex. How auditory information is processed centrally is far from clear. A feature of any periodic wave, however, complex it may be, is that it can be analysed according to what is known as Fourier's Law into its component pure tones the frequencies of which bear to one another the ratios 1 2 3 4 5 and so o n. it is a remarkable feature of the ear that it carries out just such an analysis [how] remains a matter of speculation the basilar membrane appears to be performing a mechanical form of frequency analysis (Hood) From the auditory cortex the patterns are passed to the data-processing regions in the lower (temporal) lobes of the brain, and to the emotional regions in the upper (frontal) lobes, for analysis.(McLaughlin)

As with the operation of the neural network generally, nerve impulses must all be the same and are not affected by differences in the source of the external stimulus. A quiet noise produces only a few pulses per second, a loud one several hundred per second. The pulses are identical, whatever the intensity of the stimulus, in every nerve. whether from the ear, the eye, a chemical receptor in the nose, a Pacinian corpuscle (responding to pressure on the skin) or a touch or cold receptor. The same code is used not only for signals going towards the brain, but for signals coming from it to the muscles and glands, producing behavioural responses. The only indication of their message is the organ from or to which they travel and the route which they take. The only way we know that a particular pattern of impulses is 'hearing,' in fact, the only meaningful definition of hearing, is that these patterns are travelling from the ear to the auditory cortex. As a vivid illustration, Grey Walter has said that if the tongue was connected to the auditory cortex and vinegar placed on it, 'You would taste nothing. You would hear a very loud and startling noise'(McLaughlin 1970:59).

The implications for the perception of music of this identity of nerve impulses and patterning are discussed by McLaughlin. When the incoming signal, as in the case of music, is a pattern which has no immediate function as a useful sense impression, equivalent patterns from other sense modes will be activated. The selection and succession of the musical notes may in themselves have no significance for us but the electrical patterns into which they are translated can be compared and identified with patterns from other sources.

In the brain, the patterns of tension and resolution implicit in music are translated into an electrical code of pulses, used in common for all the senses, including hearing and bodily sensations. The basic patterns of musical experience can be analysed into patterns of tensions and resolutions melodic, harmonic, rhythmic and dynamic. If the patterns of tension and resolution in the music are similar to those usually connected with body movement, touch, sight, taste or any other sense impressions, we will have a sense of association between the two or more sets of impressions amounting, to a greater or less degree, to identification. While musical patterns are strictly speaking meaningless in themselves, the fact that they are translated in the brain into the general lingua franca of all other patterns - mental patterns such as grief, expectation, fear, desire, and so forth, and bodily patterns such as hunger, pain, retention, sexual excitement, any of the tensions associated with a raising of the adrenalin level in the blood - and the corresponding resolutions - allows us to see the similarities between the musical patterns and these more personal ones. Susanne Langer (1953) makes the same point, that the tonal structures we call music bear a close logical similarity to the forms of human feeling.

Emotions

If the function of music were only to simulate the effects of simple emotions, it would not be a very important art The actual effects of great art are far more complex and constitute a synthesis of many emotions and feelings to make up a whole that is greater than the sum of its parts. We are made aware. at one and the same time, of intellectual, emotional and bodily patterns. We find ourselves experiencing a synthesis or fusing of many events, many memories. (McLaughlin)

Paul Valéry, the poet of mind and consciousness (see Sewell 1952), pondered (1974: 951 ff.) upon the "puissance illégitime" of music. Effective music, he thought, "s'adresse directement au système nerveux qu'il travaille. La musique est un massage. excitation directe et externe de toutes les fonctions qui généralement sont excitées de l'intérieur. Il ne serait pas impossible de faire une table de traductions, un dictionnaire: Musique - Mécanique neuropsychique-musculaire - Il servira à illustrer la système nerveux".

But, it may be said, most of the evidence in this section relates to the effects of music on the hearer, on the performer or the conductor and very little to the composer, the process of music production, the neurological and physiological precursors or prerequisites for the creation of music. The short answer is that the composer's neural system, the physiological bases of his emotions and perceptions, are the same as those of the performer, the conductor or the responsive listener. The composer draws the structure and the power of his composition from the same structures as determine the impact of his work. In the same way as bird-song and the response to bird-song have been shown to use directly related neural structures (Nottebohm et al. 1990) and as there are direct neural links between speech production and speech perception (Liberman and Mattingly 1985), so music-production and music-perception are two faces of the same neural complex. The structure of the composed music, the emotive and other effects the melody and harmony have, are, on this view, derived from the neural patterning associated with the composer's non-musical experience, the neural record of his own life, his own emotions and perceptual organisation, and bodily feelings of all kinds.

BIOLOGICAL LINKS BETWEEN THE ARTS

All the arts can be seen as a manifestation of one and the same impulse. The drive to the arts must surely have had a biological origin. But why do these types of behaviour exist? Why should Beethoven choose the massive labour of composition rather than eating, drinking, a family life? Maybe there was the desire to create a 'ktema es aei' (a possession for ever), in the awareness of death to survive somehow, but this does not indicate why his activity took this specifically artistic form.

The basic biological drive, impelling composers to compose, artists to paint, poets to write and even scientists to do their science is towards exploration of the perceived world (the outer world and the inner world) and the attempt to replicate it in some durable form. In a sense artists and musicians are engaged in exploration of the properties of the eye and exploration of the properties of the ear.

We are perceiving creatures set in a multi-sensory world who have acquired an awareness of our perception and even perception of our awareness of our perception. We have a drive to the externalisation of our perception, of our awareness. Externalisation is transduction - transfer from one (neurological, physiological, cerebral) system to another - conversion of simultaneous patterning into time-patterning or extended experience into immediate unextended structure. The ability to transduce in this way must depend on cross-modal connectivity in the brain. On this view the production of art is a process of cross-modal transfer, for example, from neural emotional patterning to music, painting, the words of a poem.

The artist is creating equivalent structure - moving from the perceived world to central neural patterning to externally presented form. As sensory read-in from different sources or through different channels goes to modify a central (neurally uniform) network, so read-out from the central uniform network may go to different outputs or through different channels. If this is so, there can be a kind of homoeomorphism between the various forms of artistic expression. The artistic process thus can be seen as part of, derived from an evolutionarily valuable capacity to model the world, to model oneself, and to model oneself in the world, a capacity which evolved because it served to increase the ability of the individual or the species to act more effectively and extensively in the world. There is the analogy - or parallel case, or directly-related case - of language as an instrument for modelling the world, converting internal patterning into articulatory action-patterns, sound patterns. Beyond art, one can see a similar process at work, a similar drive functioning, in science, the attempt to transduce the structure of the physical world, to externalise the scientist's understanding of the world. And it appears that scientists may even use much of the perceptual and creative methods of the artist: "Tous les hommes de science ont dû prendre conscience de ce que leur réflexion, au niveau profond, n'est pas verbale: c'est une experience imaginaire, simulé à l'aide de formes, de forces, d'interactions qui ne composent qu'à peine une 'image' au sens visuel du terme. Je me suis moi-même surpris... à m'identifier à une molécule de protéine".(Monod 1970: 170)

REFERENCES