Subject: Re: Implicit human echolocation From: Mikael Fernstrom <mikael.fernstrom@xxxxxxxx> Date: Thu, 31 May 2007 18:55:10 +0100 List-Archive:<http://lists.mcgill.ca/scripts/wa.exe?LIST=AUDITORY>--Apple-Mail-10-463448154 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=ISO-8859-1; delsp=yes; format=flowed We did an experiment on this some years back, McGrath, R., T. Waldmann, M. Fernstr=F6m (1999). Listening to Rooms and =20= Objects. Audio Engineering Society, 16th International conference on =20 spatial sound reproduction, Rovaniemi, Finland. /Mikael On 31 May 2007, at 17:26, Ewan A. Macpherson wrote: > On 31 May 2007 at 9:33, Bob Masta wrote: > >> On 30 May 2007 at 9:31, Bruno L. Giordano wrote: > >>> 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. > >> 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. > > That experiment is indeed described by Griffin (at least in "Echoes of > Bats and Men"), but was done by Supa, Cotzin & Dallenbach (1944): > "Facial vision", the perception of obstacles by the blind. Am.J.Psych. > 57:133-183. > > Blind subjects were able to detect the barrier equally well by =20 > means of > the recordings or when their faces were covered with a felt veil, thus > disproving the "facial" part. > > -- > Ewan Macpherson, Ph.D. <emacpher@xxxxxxxx> > Research Investigator, Central Systems Laboratory > Kresge Hearing Research Institute, U. Mich. > http://www-personal.umich.edu/~emacpher --Apple-Mail-10-463448154 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=ISO-8859-1 <HTML><BODY style=3D"word-wrap: break-word; -khtml-nbsp-mode: space; = -khtml-line-break: after-white-space; "><DIV>We did an experiment on = this some years back,</DIV><DIV><SPAN lang=3D"EN-GB">McGrath, R., T. = Waldmann, M. Fernstr=F6m (1999). <SPAN class=3D"Apple-style-span" = style=3D"text-decoration: underline;">Listening to Rooms and = Objects</SPAN>. Audio Engineering Society, 16th International conference = on spatial sound reproduction, Rovaniemi, Finland.</SPAN></DIV><DIV><BR = class=3D"khtml-block-placeholder"></DIV><DIV>/Mikael</DIV><BR><DIV><DIV>On= 31 May 2007, at 17:26, Ewan A. Macpherson wrote:</DIV><BR = class=3D"Apple-interchange-newline"><BLOCKQUOTE type=3D"cite"><DIV = style=3D"margin-top: 0px; margin-right: 0px; margin-bottom: 0px; = margin-left: 0px; ">On 31 May 2007 at 9:33, Bob Masta wrote:</DIV><DIV = style=3D"margin-top: 0px; margin-right: 0px; margin-bottom: 0px; = margin-left: 0px; min-height: 14px; "><BR></DIV> <BLOCKQUOTE = type=3D"cite"><DIV style=3D"margin-top: 0px; margin-right: 0px; = margin-bottom: 0px; margin-left: 0px; ">On 30 May 2007 at 9:31, Bruno L. = Giordano wrote:</DIV> </BLOCKQUOTE><DIV style=3D"margin-top: 0px; = margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: = 14px; "><BR></DIV> <BLOCKQUOTE type=3D"cite"><BLOCKQUOTE = type=3D"cite"><DIV style=3D"margin-top: 0px; margin-right: 0px; = margin-bottom: 0px; margin-left: 0px; ">An improbable single-trial = experiment could address this question:</DIV><DIV style=3D"margin-top: = 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; = ">blindfolded participants are asked to walk along a path, as long = as</DIV> </BLOCKQUOTE><DIV style=3D"margin-top: 0px; margin-right: 0px; = margin-bottom: 0px; margin-left: 0px; ">they<SPAN = class=3D"Apple-converted-space">=A0</SPAN></DIV> <BLOCKQUOTE = type=3D"cite"><DIV style=3D"margin-top: 0px; margin-right: 0px; = margin-bottom: 0px; margin-left: 0px; ">wish. They wouldn't be informed = that a wall is obstructing the path.</DIV> = </BLOCKQUOTE></BLOCKQUOTE><DIV style=3D"margin-top: 0px; margin-right: = 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; = "><BR></DIV> <BLOCKQUOTE type=3D"cite"><DIV style=3D"margin-top: 0px; = margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">Harry Erwin = has mentioned Griffin's "Listening in the Dark".</DIV><DIV = style=3D"margin-top: 0px; margin-right: 0px; margin-bottom: 0px; = margin-left: 0px; ">As I recall, this book discusses an experiement = almost</DIV><DIV style=3D"margin-top: 0px; margin-right: 0px; = margin-bottom: 0px; margin-left: 0px; ">identical to the one you = propose.<SPAN class=3D"Apple-converted-space">=A0 </SPAN>I believe = Griffin used a</DIV><DIV style=3D"margin-top: 0px; margin-right: 0px; = margin-bottom: 0px; margin-left: 0px; ">moveable barrier in a straight = hallway, set to a random<SPAN = class=3D"Apple-converted-space">=A0</SPAN></DIV><DIV style=3D"margin-top: = 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">distance = down the hall without the knowledge of the</DIV><DIV style=3D"margin-top: = 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; = ">blindfolded subject.<SPAN class=3D"Apple-converted-space">=A0 = </SPAN>The subject knew he would encounter</DIV><DIV style=3D"margin-top: = 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">the = barrier, but not where/when.</DIV><DIV style=3D"margin-top: 0px; = margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: = 14px; "><BR></DIV><DIV style=3D"margin-top: 0px; margin-right: 0px; = margin-bottom: 0px; margin-left: 0px; ">I think the experiment was = repeated with a microphone</DIV><DIV style=3D"margin-top: 0px; = margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">on a trolley = in place of the subject, and the subject would</DIV><DIV = style=3D"margin-top: 0px; margin-right: 0px; margin-bottom: 0px; = margin-left: 0px; ">then listen through headphones as the trolley was = moved</DIV><DIV style=3D"margin-top: 0px; margin-right: 0px; = margin-bottom: 0px; margin-left: 0px; ">down the hall.</DIV> = </BLOCKQUOTE><DIV style=3D"margin-top: 0px; margin-right: 0px; = margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV = style=3D"margin-top: 0px; margin-right: 0px; margin-bottom: 0px; = margin-left: 0px; ">That experiment is indeed described by Griffin (at = least in "Echoes of<SPAN = class=3D"Apple-converted-space">=A0</SPAN></DIV><DIV style=3D"margin-top: = 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">Bats and = Men"), but was done by Supa, Cotzin & Dallenbach (1944):<SPAN = class=3D"Apple-converted-space">=A0</SPAN></DIV><DIV style=3D"margin-top: = 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">"Facial = vision", the perception of obstacles by the blind. Am.J.Psych.<SPAN = class=3D"Apple-converted-space">=A0</SPAN></DIV><DIV style=3D"margin-top: = 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; = ">57:133-183.</DIV><DIV style=3D"margin-top: 0px; margin-right: 0px; = margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV = style=3D"margin-top: 0px; margin-right: 0px; margin-bottom: 0px; = margin-left: 0px; ">Blind subjects were able to detect the barrier = equally well by means of<SPAN = class=3D"Apple-converted-space">=A0</SPAN></DIV><DIV style=3D"margin-top: = 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">the = recordings or when their faces were covered with a felt veil, thus<SPAN = class=3D"Apple-converted-space">=A0</SPAN></DIV><DIV style=3D"margin-top: = 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; = ">disproving the "facial" part.</DIV><DIV style=3D"margin-top: 0px; = margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: = 14px; "><BR></DIV><DIV style=3D"margin-top: 0px; margin-right: 0px; = margin-bottom: 0px; margin-left: 0px; ">--</DIV><DIV style=3D"margin-top: = 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">Ewan = Macpherson, Ph.D.<SPAN class=3D"Apple-converted-space">=A0 </SPAN><<A = href=3D"mailto:emacpher@xxxxxxxx">emacpher@xxxxxxxx</A>></DIV><DIV = style=3D"margin-top: 0px; margin-right: 0px; margin-bottom: 0px; = margin-left: 0px; ">Research Investigator, Central Systems = Laboratory</DIV><DIV style=3D"margin-top: 0px; margin-right: 0px; = margin-bottom: 0px; margin-left: 0px; ">Kresge Hearing Research = Institute, U. Mich.</DIV><DIV style=3D"margin-top: 0px; margin-right: = 0px; margin-bottom: 0px; margin-left: 0px; "><A = href=3D"http://www-personal.umich.edu/~emacpher">http://www-personal.umich= .edu/~emacpher</A></DIV> </BLOCKQUOTE></DIV><BR></BODY></HTML>= --Apple-Mail-10-463448154--