Re: Implicit human echolocation (Thomas G Brennan )

Subject: Re: Implicit human echolocation
From:    Thomas G Brennan  <g_brennantg@xxxxxxxx>
Date:    Fri, 1 Jun 2007 08:49:48 -0500

Peter, I've done a few studies with blind folks that I've never published as its difficultish for an individual to publish alonw. I have found glasses to be problematic in the real mobility world. One problem with lab studies is that you don't have real world inputs and the signals become so undifferentiated that they can be hard to hear, especially in the case of "passive" echo location which is really not passive at all or we wouldn't be able to hear it. I have some frequency spread data that I've published in an o&m book that shows approximately where some frequency splits are for differing kinds of echo location tasks. Both the frequencies that I believe are used as well as how you process the sounds differ for different tasks and in different environments. What really made me a believer in cultural echo location (I like that term) is spending some time in Mexico working with some blind children there. Even snow creates such a different environment that echo location skills must nearly be thrown out the window and relearned for snow specific environments and even then you almost have to use active location and it doesn't do much good. Tom Tom Brennan KD5VIJ, CCC-A/SLP web page

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