Subject: Re: Implicit human echolocation From: Bob Masta <audio@xxxxxxxx> Date: Thu, 31 May 2007 09:33:05 -0400 List-Archive:<http://lists.mcgill.ca/scripts/wa.exe?LIST=AUDITORY>On 30 May 2007 at 9:31, Bruno L. Giordano wrote: > Hello, > > I have a general knowledge of the literature on human echolocation: > sighted-blindfolded listeners are capable of locating nearby surfaces > from the reflections of self-generated sounds, when they are instructed > to do so. > > However, does echolocation persist in absence of explicit instructions? > > An improbable single-trial experiment could address this question: > blindfolded participants are asked to walk along a path, as long as they > wish. They wouldn't be informed that a wall is obstructing the path. > Unfortunately, the number of injuries would measure implicit > echolocation abilities. > > Is anybody aware of related, more ethical studies? > Harry Erwin has mentioned Griffin's "Listening in the Dark". As I recall, this book discusses an experiement almost identical to the one you propose. I believe Griffin used a moveable barrier in a straight hallway, set to a random distance down the hall without the knowledge of the blindfolded subject. The subject knew he would encounter the barrier, but not where/when. I think the experiment was repeated with a microphone on a trolley in place of the subject, and the subject would then listen through headphones as the trolley was moved down the hall. Best regards, Bob Masta D A Q A R T A Data AcQuisition And Real-Time Analysis www.daqarta.com Scope, Spectrum, Spectrogram, Signal Generator Science with your sound card!