Wednesday, August 25, 2021

Secret Scince Club Zoom Lecture Recap: Mind and Music

Tonight, my great and good friends of the Secret Science Club are presenting a Zoom lecture with neuroscientist Dr David Sulzer of the Psychiatry, Neurology, and Pharmacology departments of Columbia University Medical Center.  Dr Sulzer is also a musician and composer, and an early SSC lecturer (sadly, before I started blogging).  He is cofounder of the Thai Elephant Orchestra, and the author of Music, Math, and Mind: The Physics and Neuroscience of Music.

Dr Sulzer told us he would be asking two broad questions:  Do other species hear music like we do? Can other species play musical instruments?  First, though, we would have to get some math and physics out of the way.

Sound is a wave in the air.  The wavelength is the length of a wave from corresponding parts, amplitude is the height of the wave.  Molecules are pushed together and pulled apart (water can't be compressed, when squeezed, it's amplitude rises  air can be squeezed.  The speed of a recurring wave is the frequency.  Humans can hear sounds of a frquencye of about 20 Hertz (waves per second)  an elephant can hear sounds at 1 Hz.  Human teenagers can hear up to about 20000 Hz, while adults lose some hearing ability and hear up to 15,000 Hz).

Dr Sulzer illustrated waves in the air by describing the workings of a siren, originally a rotating, perforated wheel on which compressed air is blown.  He used the Audacity program to illustrate frequency, and the harmonics which 'spice' a sound.  He also used a piano to play notes corresponding with frequencies.  He also gave us an experiment to perform, setting up a speaker in a hallway, then walking toward it to hear the amplitude change of the waves as a change in volume.  

Musical notes and harmonics are whole note multiples of frequency.  Pythagoras (Dr Sulzer joked that he is Christ-like because he wrote no books but his followers did) opined that the universe should make sense.  The universe should be explainable in recurring series of multiples.  From the quantum level to the cosmic level, these recurrences exist.  An octave is twice the frequency of the lower octave.

Dr Sulzer displayed a photo of a replica of a swan-wingbone flute (35,000 years old) that employs a pentatonic scale.  He then returned to Audacity, to demonstrate that adding harmonics always produces a periodic wave.    He assured us that this was all leading to something.  He then played a dissonant note, which messes with the period wave.  Notes that aren't harmonic can make beats, using interference to alter amplitude, cancelling out sounds.

Dr Sulzer then moved on to the neuroscience of music, where we recognize consonance and dissonance.  Dr Wilder Penfield, a pioneer in the surgical treatment of epilepsy, also studied the cortical regions which determine muscle movements and sensory inputs.  Nima Mesgarani studies the role of the cortex in analyzing sound,  mapping where plosives, fricatives, and nasals are analyzed.  Even ferrets can distinguish these sounds in human speech.

Do other animals hear like we do?  The frequency ranges can be very different (bats can hear up to 200K Hz, elephants hear about an octave lower that humans), but noise and consonance are built on physics.

Can other species play musical instruments?  Caged zebra finches can trigger musical sounds, even with no training or reward.  Would wild birds play musical instruments?  Mockingbirds have a wide musical vocabulary, and might be more likely to do so than, say, pigeons.  Susan Savage-Rumbaugh has studied bonobos interacting with musical instruments.  He then featured the Thai Elephant Orchestra, noting that the instruments provided to the elephants were chosen due to their popularity among the locals, such as the marimba-like ranat ek.  He also noted that elephants love harmonicas.

Dr Sulzer ended his lecture with a note about Asian elephant conservation.  In 1900, there were 100,000 domesticated elephants in Thailand. They were working animals.  Now, the population is about 3,700, since the elephants are not needed for work.  Logging was banned in 1989, so tourism is the only work.  

What other species play musical instruments?  Some songbirds, bonobos, elephants, but we are only scratching the surface.  Instruments must be ergonomic for other species, and must produce attractive sounds for those species.  Bad instruments are not appealing. 

The lecture was followed with a Q&A session.  Dorian started the process by asking if animals began by playing sounds in their own voices- zebra finches did, but developed musical tastes, playing other songbirds songs, and human music (but they avoided canary sounds because canaries are big and scary).  Regarding the Thai elephants' taste, they prefer 'hillbilly' music, the pentatonic music of the Northern Thai musicians who use fiddles- this is the music of their mahouts and caretakers, and the elephants are used to it.  Elephants are social animals, and this is the music of social gatherings of both humans and elephants.  African elephants are no longer domesticated, but they once were, such as Hannibal's famous elephants, so their musical tastes are unknown.  Why is some music scary?  How does the Devil's Interval work?  In consonant music, the notes reinforce each other.  While some dissonance is acceptable, it can be resolved.  If the frequencies are divided exactly in half, an irrational number results- according to legend, the Pythagorians drowned the person who discover.

Some bastard in the audience asked about the neurology of audition among different animal lineages- the auditory cortex is pretty well known, but the areas of the brain that interpret sound need to be studied better.  Other animals with a cortex have similar auditory areas, even though their ears may be radically different (such as insects which have ears on their knees).  Even among insects and crustaceans. the mechanisms are similar Marta Novotny, Lisa Olson of Columbia study bush crickets and katydids.

Another question involved animals which hear low-frequency sounds, such as whales.  It is possible that fin whales, before the noise of mechanized shipping, could have heard each other from hundreds of miles away.  Certain animals, such as frogs, have limited frequency ranges at which they hear.  Hearing is really the detection of vibrations, so even moths can 'hear' each other moving.

Another question involved people who love dissonant music- people love to add noise to their music, overblowing saxophones, using guitar feedback, adding additional noisemakers to instruments.  Synth pioneers such as Wendy Carlos immediately set about finding ways to 'dirty up' synthesized sounds. 

Another questioner asked if animals sounds also followed pentatonic scales, Dr Sulzer recommended the Cornell Laboratory of Ornithology's sound analyzing Raven app, and said that some bird songs have the octaves built in, he urged her to study this topic herself.

Can elephants maintain a steady beat?  They tend to be better than humans at it, but we have to be careful about anthropomorphizing their behavior.  Also, is this spontaneously play or training?  It's a combination of both.  The zebra finches weren't trained at all, but learn their songs from their fathers, and the elephants were trained for about five minutes.

As an added bonus, SSC alum Dr Diana Reiss chimed in during the Q&A to note that a lot of dolphin 'hearing' takes place through the jawbone after lauding Dr Sulzer's lecture.  It was a fun instance of Secret Science Synergy in action.

Once again, the Secret Science Club delivered a fantastic lecture, and Dr Sulzer managed to sneak in math and physics along with the fun stuff about musical elephants, kinda like making us eat our vegetables before dessert.  He added musical flourishes to illustrate his

For a taste of the SSC experience, here's a video of Dr Sulzer talking about the subject of his book:

Pour yourself a nice beverage and soak in that SCIENCE!!!!

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