Hardwired

There's a funny thing that happens occasionally on my way home from work.  As I reach Porter Square, it's not uncommon for the infamous Porter Square escalator  to be out of service, which makes for 6-story vertical climb.  Not fun.  But the interesting thing is what happens when I try to step on to the stalled escalator:  A brief but intense moment of vertigo as my brain reacts to the split second delay before my foot makes contact with the stair.  I know the escalator is not moving. I know not to expect the tread to rise to meet my descending foot.  But somehow, and this is the part that fascinates me, some part of my brain has been optimized purely for getting on and off escalators, and yet it isn't quite able to figure out that a non-working escalator is just a stair.

That's the odd thing about brains - we experience reality as objective and fixed, but behind the scenes our minds are doing all kinds of weird processing to make the world more comprehensible.  Optical illusions are the classic example used in Cog Sci 101 classes.  My personal favorites are the gray contrast illusions, since their application to the real world is so clear:

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The gray bar in the center is the exact same shade throughout, and yet we see it as lighter on one side and darker on the other.  Our visual cortex is 'enchancing' the contrast in order to improve edge-detection.  This has huge advantages in the natural world, especially where you might need to distingush a camouflaged predator (or prey) from its surroundings.

So by now some of my readers (maybe even both of you) might be wondering what this has to do with music.  The fascinating thing about music (at least for me) is that it exists at all, let alone why it is so prevalent throughout human society.  Every culture has it's own form, and even music in another language can attract passionate fans.  It appears to have no obvious evolutionary value, and yet this appreciation for music has real neuro-psychological underpinning. Arstechnica has a great writeup on research showing how listening to a beloved piece of music causes dopamine releases in the brain. This activation of the mesolimbic system appears to be associated with both mental reward and memory.

But why does it exist?  Babies can distinguish the "mood" of music as early as 5 months of age: does this mean that music is hardwired into us from birth?  Or does the substantial amount of brain dedicated to auditory processing simply respond well to such complex stimuli?  I don't know of any definitive answers to these questions, but as I read more I'll post what I find out here.