Melody, harmony, timbre, rhythm and lyrics are perceived as movement, as meaning, and as emotion in the brain. The unique power of music to harness nature, culture and mind plays out in the interaction of music and the brain.
Some consider vision the major sense, the way our view of the world is most organized. But, this view overlooks the unique characteristics of sound. Hearing may be the most important sense.
Sound is uniquely affected by the environment, not just what can be seen, but around and behind objects, and at great distances. In life, buildings, spaces, acoustic properties, roads, objects very far away and all aspects of the environment determine what we hear. There is never silence, but just different kinds of background noise. In fact, listening to the silence or quiet sounds of nature has very positive effects on health, a form of sensory fasting.
Even in sound proof chambers, still there is no silence, but rather the sounds of air molecules vibrating in the ear canals, heart and breathing sounds, and even electricity in the brain.
Everything Has Sound Vibrations
Many vibrations in the universe are sound waves, ranging from the highest frequency of vibrating molecules (energized cesium -133) to the lowest frequency vibrations of a black hole (57 octaves below middle C). There are sound vibrations everywhere. Even the sense of touch feels vibrations like hearing, but at different frequencies.
Sight acts very quickly. Touch can act slow (light touch) or fast (pain) but in a narrow range. But, sounds can act in a millisecond (bats hearing echoes) or very slow for hours or days, like the humpback whales listening to songs for hours. Our ears are exquisitely sensitive to the shortest and longest sounds, and everything in life produces sounds.
The thoughts and conversations in our head are auditory experiences. Even deaf people seem to be “hearing” this internal conversation, not “seeing” their thoughts. In meditation, sound is often the major experience, listening to the background sounds, or the “celestial music”.
Sounds are especially able to evoke emotions and memories. The effects of sounds are not only determined by physics and mathematics, but culture and individual preferences.
The Uniqueness of Rhythmic Sound
Rhythm has its own unique language and coordinates movement and emotion in human beings, such as the actions and emotions of dancers. But, rhythm has other profound effects on the brain, including influencing perception and thinking.
Examples of rhythm’s effects include how tribes unite in ceremonies, how armies march into battle, how some types of gospel music propels congregations, and also the punctuation of speech.
Studies show that learning and memory linked to specific beats in a rhythm stimulated increased learning ability. For example, expecting the emphasis on the fourth beat increased cognitive performance if the learning or perception task is done on the fourth beat.
Brain alpha and beta EEG rhythms synchronized to a beat and visual cortex sensory stimulus was greater on a specific beat. In perception tests, details are more likely to be seen on the emphasized beats.
Performing the same research with visual forms of beats, like a bouncing ball, did not increase learning or perception.
Rhythm can induce hypnosis and mind altering states
There are differences in brain effects between the visual arts and music. In psychotherapy art is used to show emotions and personal associations, and to examine the sense of self.
In music memories are triggered. Rhythm has strong effects on emotions without any specific interpretation.
The Brain Makes Sound Simple
It is not commonly understood that a musical note is not simple, but is made up of many parts. In fact, it is so complex that physicists have not yet figured out how the brain comprehends the many factors contributing to an individual note. A recent study showed that the current physics theory of sound using the Fourier transform does not adequately model how the brain analyzes sound. In fact these equations, used by Einstein to analyze light vibrations, are not nearly complex enough by a factor of 13.
But, the brain takes a very complex sensory input and makes it into the perceived simple sound.
The pure simple tone we hear is actually many different frequencies vibrating above the primary note. When a simple note is made, such as striking a triangle, a hammer hitting a string in a piano, a column of air vibrating in a wind instrument, or a bow moving accross the string of a violin, many different frequencies occur, not just the one we associate with “that note.”
These vibrations accompanying any note are called harmonics, or overtones. They occur in multiples of the base frequency, for example if the frequency is a 100 Hertz (vibrations per second) the overtones will be 100, 200, 300, 400, 500, etc… This is written mathematically with ratios 1:2:3:4:5:6. These overtones include the well-known octave, the “perfect fifth” and many other less well-known frequencies. All of these different tones blend into one sound fooling the ear. The other measure of the sound wave is wavelength (wavelength x frequency = speed of sound) and these would be written in the harmonic series – 1, 1/2, 1/3, 1/4, 1/5, 1/6, … etc.
These simple overtones apply to the straightforward situations noted above, such as a vibrating string or air column, but not to the large round surface of a drum. With a much more complicated vibrating surface, the overtones and harmonics are vastly more complex in a drum beat.
Western music tends to use the first few simple harmonics as the basis for chords, scales and melodies. However, even using simple harmonics, chords become very complex because each note in a chord triggers other harmonics which all interact through a process called wave interference. Using different scales and keys rapidly becomes mathematically very complex. But, our ears simplify it and hear the same simple harmonics even when transposed into other keys.
Further complications for understanding sounds come from reverberations from all aspects of the environment where the sound is made or heard. The brain combines all of the reverberations and all the harmonics into the illusion of one simple sound.
There are actually many other factors that complicate the sound. Timbre is the unique sound quality, such as voice, clarinet, guitar, or ocean sounds. Sound characteristics that affect the timbre involve the “sound envelope” including characteristics like attack time, decay, sustain, and release. Different timbres emphasize different parts of the harmonic series. Study of the envelope has used the Fourier transform to break a sound wave into components.
In humans the voice sounds different in each person because of differences in vocal chords, oral cavity, facial bone structure and many other characteristics affecting the emphasis of the complex waves.
Even beyond these factors, the brain is able to analyze spatial and temporal details of sound. The brain determines where the noise is coming from and whether it is moving toward us or not. All of this analysis occurs in milliseconds.
Culture Makes Different Scales
Scales around the world use between four and seven notes in the octave with different sized intervals. The octave is double the frequency of the base, or main low note. The western scale breaks the octave into 12 semitones and then uses these to make eight steps, the eighth being the octave.
Indian classical music uses microtonal scales with steps smaller than the western semitone. This Indian scale divides the octave into srutis, the smallest interval a human can hear – one system has 22 steps. There are many other systems around the world. Modern synthesizers allow an infinite number of different scales and steps.
But if the interval between two notes becomes too small, it sounds dissonant, or unpleasant. This may be caused by the interference patterns of notes that are very similar creating a loud beating sound (sometimes this beating phenomenon of interfering air waves can occur while driving in a car, with certain arrangements of open windows.) This chaotic interference pattern, and our ear’s basilar membrane find this uncomfortable.
The brain of babies, animals and almost all cultures recognize the octave and maybe fifth as special. Consonance may be from convention, or it might be from interference patterns in the basal membrane of the ear. Some western scientists believe that western scale has the least dissonances, but this is probably determined culturally not scientifically. A question arises whether specific brain structures for acoustic processing are related to western composition techniques such as counterpoint – simultaneous different musical melodies where each moment the pair of notes are harmonious. But other researchers are convinced that all pleasure or dissonance of music is culturally trained.
Some believe that specific scales or chords express specific emotions, but this also is probably culturally determined. Music is “sad” when a major chord (major third interval – four half steps) becomes minor (minor third interval – three half steps). However, many “happy” pieces do this same thing in Hungarian, Spanish, Irish, Medieval church music, and troubadours.
In a future post, there will be more about emotional aspects and whether it is scientific or culturally determined.
One-celled microbes respond to multiple different stimuli at once. Deciphering responses to light, molecular touch, sound vibrations, and acidity of the water is the first example of multi-sensory integration. The living being wants to integrate as much information as is available. The brain is built for multi sensory integration and music is the master multi sensory stimulus.
Since music is inherently multi sensory, it is critical to understand the multi sensory brain before attempting to understand what music learning does to the brain. Senses are much more closely related than previously thought. The brain combines as much information as it can from as many senses as possible. There are many common examples of multiple senses in every day life.
Rapid changes in function of brain regions occur from one sense to another with deprivation of a sense.
- After two hours of being blindfolded, extra touch signals are transmitted through visual brain centers.
- Blind people use the visual cortex for extra hearing information.
- The deaf are much better at lip reading.
- The blind are better at using echolation.
Many daily functions are enhanced by multiple senses:
- Normal speech actually involves visually observing lips of speakers.
- Chewing on food increases enjoyment of food.
- The effects of taste can be altered by different sounds.
- Body posture is influenced by vision.
Brain may interpret speech from ears, eyes, or skin.
- Helen Keller interpreted speech by placing fingers on lips, cheeks and neck.
- During lip reading auditory brain is active – the auditory brain also sees.
- Videos of speech turned into pixels can still be lip-read.
- People can recognize speech reduced to sine ways.
- Listening to a familiar voice stimulates brain center for faces.
- Observing speech alters what is heard. A video speaker says “ga” while audio plays “ba.” Instead of hearing “ga”, the we hear “ba.”
Smell, sight and sound changes taste.
- An orange drink will taste cherry if colored red.
Watching and position:
- If watching a waterfall and touching a desk, hands feel the desk rising.
- Watching near or far object changes observers posture.
Hearing crunch sounds while eating potato chips determined whether they tasted stale or new.
The brain is not built in isolated modules as some think, but is melding information together constantly. When three different senses are connected they all impact on specific single neurons and have effects either to amplify or decrease the effect of that neuron.
Music in the Multi Sensory Brain
Imaging studies show that brains see music as motion and activity. Imaging during music shows the same regions of the brain as in sport, signing our name, and emotions.
When musicians listen to music their brain acts as if they are playing, when looking at sheet music motor planning centers are activated.
- Watching dancers stimulates our muscles as if we are dancing.
- Dancers watching a similar style have active MRI, if a different style less active.
- Pianists’ brains show very active MRI when listening to music as if planning and playing.
Power of Addiction and Music
People get intense pleasure in listening to specific songs and in specific musical social settings. The enjoyment of playing and listening to songs that give pleasure increases plasticity learning effects.
Like drugs music hijacks the reward (addiction) brain centers which makes the motor memory much more powerful. One reason that music is such a powerful stimulus for brain plasticity is that it jumpstarts the learning process with the effects of the reward brain circuits.
Music and the Brain
Sound is, perhaps, the most complete and primal sense being influenced by all aspects of the environment, by our body, and by the unique multi sensory nervous system. The brain makes one sound perception from thousands of characteristics and harmonics. The melodies, harmonies, timbre, rhythm and lyrics are perceived as movement, as meaning,and as emotion. Music effects are as powerful as drugs.
The next post will show the unique effects of musical training in enhancing capacities throughout the life cycle, increasing brain plasticity, and in treating illness. After that posts will discuss music and improvisation, emotion, spirituality and evolution.