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Genes Found That Respond To Distance

[ 2 ] August 20, 2010

A new study from the University of Illinois shows that gene expression in a bee’s brain changes when the bee perceives long and short distances.  The researchers used an ingenious little trick -  If the bee’s environment is “busy” (patterned walls with lots of disordered images) rather than “sparse” (walls with a more plain pattern), it perceives its traveling distance as longer.  This perception is measured by looking at the bee’s “dance,” the behavior it uses to communicate the location of food sources.  The dances are different in both experimental situations, even though both distances are the same.  Furthermore, gene expression in brain areas involved in vision and memory differs between the two environments, implying that there are genetic factors responsive to distance (and apparently prone to error).  This work furthers the idea the genome isn’t merely a static set of instructions for organisms – it’s dynamic and responsive.

Five Notes For All

[ 0 ] August 20, 2010

Are We Wired for Music?

by Sam McDougle

I was recently leafing through Jared Diamond’s bestseller “Guns, Germs, and Steel” and was reminded of the prevailing idea in biological anthropology that humans first colonized the Americas  around 15,000 years ago (give or take a couple thousand years).  I had just posted on this site about Leonard Bernstein’s Harvard lectures and his thoughts concerning the universality of the five-note “pentatonic scale,” so I began to think about Native American music and its pentatonic nature.

The centrality of the flute in Native American music then reminded me of a study in Nature published last year, that reported the oldest ever archeological evidence of music:  A 35,000 year old flute carved from the bone of a vulture.  While the exact tones produced by the flute remain unknown, it had a curious number of holes:  5.  I also recently stumbled on a research article in the journal Infant Behavior and Development on the language of mothers and their infants – the authors showed that infants and their mothers coordinate their pitches harmonically while they speak, and the go-to pitches were often within a pentatonic scale.  Throw in the pentatonic’s ubiquity in Eurasian and African traditional music and the picture is pretty clear – these 5 notes are genetic.

The universality of the pentatonic scale in world music is not a new idea.  However, the idea that it could be biological is more controversial.

***

The acoustic signatures of human speech have been attributed to the efficacy of a harmonic series, which is a tone that resonates with a fundamental frequency (the ‘note’) and a group of overtones that are proportionally spaced apart.  A harmonic series is elicited by structures like human vocal chords, a bird’s syrinx (their singing organs) and a guitar string – the regularity of a harmonic series allows animals to differentiate their friend’s communications from the disordered noise of everyday life.   In other words, we speak in notes.  But why arrange these notes into a scale?

Kamraan Gill and Dale Purves argue that humans are drawn to musical scales because scales represent a harmonic series similar to human speech:

“The component intervals of the most widely used scales throughout history and across cultures are those with the greatest overall spectral similarity to a harmonic series. These findings suggest that humans prefer tone combinations that reflect the spectral characteristics of conspecific vocalizations (Gill and Purves, 2010).”

In other words, we are drawn to scales because they acoustically resemble speech, and we are drawn to speech for obvious reasons.  But what do notes arranged in scales (music) communicate that speech doesn’t?

Another line of new research suggests that this question is misguided.  Instead of separating music from speech and finding obvious functional differences, we have to look deeper at the similarities.  In a new article in the psychology journal Emotion, Megan Curtis of Tufts University argues that the defining pitch intervals of both sad, “minor,” and happy, “major,” music can also be heard in normal speech.

Curtis recorded professional actresses speaking neutral two-syllable phrases (i.e. “Let’s Go”) with various emotional signatures, like “sadness” and “pleasantness.” The actresses typically uttered a minor 3rd interval when expressing sadness and the major 3rd interval when expressing happiness. Furthermore, listeners overwhelmingly heard “sadness” in the minor third and “pleasantness” in the major third – it appears that the pitch of spoken words communicates emotion in the same way music does.

Intriguingly,  these intervals play an important role in differentiating the major and minor pentatonic scales.

***

Noam Chomsky put forth the idea of a “universal grammar” in language – a cross-cultural, biologically ordained set of syntactical rules that turn words into sentences.  I suspect that a “universal musical grammar” will eventually be added to his model.  Subjects and verbs are universals in human language, perhaps the pentatonic scale is one too.

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Leanord Bernstein on the Universal Linguistics of Music

[ 2 ] August 18, 2010

The Chomskian approach of the “universal grammar” of language has been applied to many human phenomenon, including morality and music.  For instance, it has been well established by both laboratory psychologists and anthropologists that the five-note pentatonic scale is a human universal, and can be found in musics from every corner of the globe (some recent research even asserts that when babies and their mothers communicate, they often use the pentatonic scale).  In 1973, Leonard Bernstein gave a six-part lecture at Harvard University, and in this clip (6:10), he explains how children around the world tease one another (‘nanana’) using three specific harmonic intervals — intervals that are part of that pentatonic scale.  If you have the time (6 hours, that is), make sure to check out the rest of his lectures on “Musical Phonology,” all of which are on youtube.

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Watch A Robot Jam Out On The Marimba

[ 7 ] August 15, 2010

Ryan Nikolaidis, a PhD student at the Georgia Tech Center for Music Technology, has invented a robot that can improvise on the marimba.  The robot, “Shimon,” uses real-time programmed algorithms that calculate tempo, rhythm, and harmony as the music plays.  While it may not be the most moving music, it’s still pretty awesome (especially the head-bobbing.)

You Silly Monkey!

[ 3 ] August 13, 2010

Laurie Santos, a Yale Psychologist, studies primate cognition.  In here recent TED talk, she lucidly explains how monkeys show the same economic riskiness as we do, treating economic losses differently than gains.  I wonder if there’s a Capuchin monkey recession going on that we don’t know about…


The Anxious Apple Doesn't Tremble Far From The Tree

[ 3 ] August 11, 2010

In a new research article in Nature,  Jonathan Oler and his team show that chronic anxiety is partly heritable. The form of clinical anxiety they studied is termed “Anxious Temperament” (AT), and Olen describes AT as,

“A trait-like phenotype evident early in life that is characterized by increased behavioral and physiological reactivity to mildly threatening stimuli (Olen et al, 2010).”

The researchers studied a large population of rhesus Monkeys (200+); by eliciting anxiety in the monkeys while analyzing their brains using PET scans, they found that “the central nucleus region of the amygdala and the anterior hippocampus are key components of the neural circuit predictive of AT.”  Furthermore, the hippocampal-driven anxiety response was often seen in closely related individuals.  I wonder what Woody Allen’s folks were like…

“Early in life, I was visited by the bluebird of anxiety.”

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