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Re: classical (and fun) experiments in psychoacoustics?

I'll add my favorite quick+dirty demo that I often use for impromptu talks to young students or general lay audiences. The topic is a bit arcane, but the demo is incredibly robust. This demonstrates how we use the learned spectral filter shape of our pinna to localize sounds in elevation.

Ask for a plucky volunteer to sit in front of the group. This works best if there is 1-3 meters of space in front of the subject. I stand in front of teh subject and reach into my pocket for a highly scientific and precise measuring instrument--my set of house keys. With the subject's eyes closed, I rapidly shake my keys at different heights and have the subject point to where s/he heard the sound. I do a little side to side as well. Subjects are generally perfect. Audience is impressed.

The subject then slightly fold his/her pinna, or flattens the pinna, or (less robust) cups the pinna with hands. The localization experiment is repeated, with the subject hold the pinna during then shaking and then pointing. Invariably, the subject points straight ahead, no matter what the actual elevation of the keys was. General hilarity and audience appreciation ensues.

The same demo for horizontal can be done, but I've found the result is generally an error rather than abject failure of localization.

I like this demo because of the "impromptu" nature of the materials and methods, helping tie in our esoteric psychoacoustic ideas to real-world experience.


: Peter Marvit, PhD
:<pmarvit at gmail dot com OR pmarvit at psyc dot umd dot edu>
: Psychology Department, University of Maryland, College Park
: College Park, MD 20742
: (lab) 301-405-5940    (fax) 301-314-9566