Subject: Re: An Auditory Illusion From: Al Bregman <bregman(at)hebb.psych.mcgill.ca> Date: Mon, 19 May 1997 16:39:52 -0400Dear Christian, I am well aware of the correlation theory of von der Malsburg and its implementation in models by DeLiang Wang. However, this will not solve the problem. In your example, if BOTH states of affairs were present together, namely a red ball on a blue table AND a blue ball on a red table, the correlation method would be powerless to achieve the correct groupings. Since one table is red, the firing of RED and TABLE must be synchronized. Since the other table is blue, BLUE and TABLE must also be synchronized. Following the argument to completion implies that all four concepts must be synchronized. What we need is two separate instantiations of RED, one bound to TABLE, the other bound to BALL. The auditory parallel would be a male voice saying "happy" on the left and a female voice saying "happy" on the right, asynchronously. HAPPY would become bound to (synchronized to) MALE, FEMALE, LEFT, and RIGHT, synchronizing everything with everything else, and losing the particular binding of MALE with LEFT and FEMALE with RIGHT. The problem exists whenever the same node has to be in two different bindings at the same time, whether the binding is achieved by correlation of firing or otherwise. - Al -------------------------------------------------------------- On Sun, 18 May 1997, Christian Kaernbach wrote: > Dear Al, > > > But consider the following two cases: > > 1. One sees a red ball on a blue table. > > 2. One sees a blue ball on a red table. > > According to a "node" theory, in both cases the nodes representing > > red, blue, ball, on and table are activated. What then is the > > difference? The two cases require a different arrangement of the > > same ideas, but node-based theories cannot express this. > > The (now) "classical" solution to this problem is synchronicity, The > cell assembly for RED and the cell assembly for BALL fire in > synchrony if they are to express that it is the ball that is red. > This idea dates back to the 70es (Christoph von der Malsburg, "A > correlation theory of brain function", he actually cites someone from > last century who had the same idea) but was confirmed only recently > (1991 or so, Gray, Konig, Engel, Singer, in Nature: binding by > motion). > > Christian > --- > Dr. Christian Kaernbach > Institut fuer Allgemeine Psychologie > Universitaet Leipzig > > Seeburgstr. 14-20 Tel.: +49 341 97-35968 (secr. 35960) > 04 103 Leipzig Fax: +49 341 97-35969 > Germany e-mail chris(at)psychologie.uni-leipzig.de >