Subject: Re: Implicit human echolocation From: Thomas G Brennan <g_brennantg@xxxxxxxx> Date: Fri, 1 Jun 2007 10:16:25 -0500 List-Archive:<http://lists.mcgill.ca/scripts/wa.exe?LIST=AUDITORY>I did o&m training to be a trainer but never bothered to pay the certification etc. That gave me a much better handle than just having had o&m training myself as to the kinds of things you must consider. It seems the ideal would be for someone with o&m training, a blind person, and a psychoacoustics expert to work together to design such experiments and run them on blind people, preferably congenitally blinded people. Of course, any time you're doing environmental testing you have the problem of uncontrolable variables but that's a bit of what the real world is all about when we echo locate. I've also done some work with hearing aid clients and echo location and have found some frequency issues and that, in general, once you get above a moderate loss you're not likely to be able to do anything useful with echo location no matter how good the training. For truly good passive location you really pretty much need to have no hearing loss. My wife just had her eyes removed on Valentine's Day this year. That has really made me wonder about research concerning echo location in such cases and its changes. Obviously there is an extremely small population to work with. Spacial issues would also be interesting to investigate. She and I both found major alterations in our spacial worlds after surgery and mine has never gone back to what it was. Dee's is too new but other blind folks I've talked to who have had some form of removal of the eyes (filling with oil is a different issue) have had varying degrees of spacial alteration and all who use it have reported to me changes in echo location mapping and how they use the information they obtain. Tom Tom Brennan KD5VIJ, CCC-A/SLP web page http://titan.sfasu.edu/~g_brennantg/sonicpage.html