Facing the Music

OK, this post is just an addendum to Elias's report, live from the scene at ARO. I should add here that me and Elias have long discussed the 'special' nature of music and speech. I'd like to believe that audition evolved first as a distant-stimulus sensor and communication sounds evolved later to exploit this. This fact may have profound influences on the way we think about auditory memory, for example. Mort Mishkin gave a talk at APAN last year (my pre-blog days, also known as the Dark Ages) where he put forward a hypothesis that nobody really liked. From lesion experiments of multiple areas in monkey (including the medial temporal lobe, entorhinal cortex and the amygdala), Mishkin thought that maybe auditory long term memory did not exist in the same functional form as visual long term memory (in the sense that a temporal sequence of activity being stored to remember sounds). Mishkin did not offer alternatives, but I think it is clear this suggests some associative form.

Our intuition here is that speech and music may share common features as both involve explicitly remembering prosody - longer temporal features. I'm a musician (sort of), and I tend to remember Gilmour's searing solos in a lexical way that's more like remembering speech (actual speech itself, not an abstracted version of the content/meaning of speech). I think this may be a somewhat general principle... that speech and music are remembered by the way they are produced.

On the other hand, when I try and remember my auditory environment, I tend to describe it in terms of objects present and the sounds they generated... like a clock ticking or a ventilation duct's noisy humming. In this case the memory is more abstract - the actual temporal sequence of sounds are associated with the source and the source and it's location are remembered. It seems to be a more efficient way of doing things, and may explain what Mishkin saw. It may be relatively easy to do an fMRI study to test this, if done right, it could go a long way.

While the front-end mechanisms for speech/music/sounds may be the same, there may be important differences over how these stimuli are treated at higher stages of processing, and so the transitive logic Elias was talking about may not hold at several levels. While I'm not against studying the "representation" of music in its own right (and it should be studied), I do come out strongly against suggestions that it is a way to study auditory processing - see Elias's report on Griffith's talk, for example.

But the bottom line is: audition, independent of speech and music does exist... and needs to be studied too.
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