Subject: RE/ an auditory illusion From: Pierre Divenyi <marva4!EarLab!pierre(at)UCDAVIS.EDU> Date: Fri, 16 May 1997 15:36:22 GMTAl, Your proof that Dick's auditory illusion constitutes the deciding vote for sending computers, rather than brains, to Heaven, may be to the point but I have to remind you that such a view seems to depart from some earlier ones you expressed in your classic 1991 opus. It appears pretty clear that, when both Voice A and Voice B say (simultaneously) "X", we have a Greek chorus (of two) which, through a single loudspeaker at least, should form a single stream because both voices share the same temporal structure which must prompt the system to group all components together. So, all this is a matter of grouping -- i.e., segregation. Which brings me to the following structure consisting of two intermingled events: Talker A says "X", while Talker B says "Y". If the (male) listener happens to perceive the structure * (asterisk as in linguistics) Talker A says "Y", while Talker B says "X", is he considered as having segregated the two events? Before taking a general vote on this, let me just forcefully express my negative opinion. No, because Talker A is the listener's wife and "X" was the utterance "Come here, love", while Talker B was another, definitely attractive female unknown to the wife. Utterance "Y" is irrelevant -- if the listener responds as if he obtained the above (incorrect) percept, the next thing he receives will be the divorce papers. So, symbol-manipulating systems can save your marriage while node-based ones can, at best, serve you with an alibi. Forget heaven. It was thanks to recognizing the subjective utility of discriminating between the two above structures that I proposed at the 1995 Mohonk meeting, and have continued to do ever since, that it is essential to associate a particular **value** (e.g., blue, red) with a particular attribute (=type, e.g., ball, table) for a scene to be correctly analyzed. In other words, correctly recognizing the mere PRESENCE of types and values does not lead to segregation of streams/events UNLESS the type-value association is correct. The positive fallout of all this is that segregation can be easily measured with a psychophysical paradigm (e.g., 2AFC) and can be learned through feedback. Pierre Divenyi **************************************************************************** Pierre Divenyi Speech and Hearing Research (151) V.A. Medical Center, Martinez, CA 94553, USA Phone: (510) 370-6745; Fax: (510) 228-5738 E-mail : PDivenyi(at)ucdavis.edu ****************************************************************************