Subject: Re: perceptual segregation of sound From: Ranjit Randhawa <rsran@xxxxxxxx> Date: Thu, 27 Apr 2006 11:17:15 -0400Dear All, As my own research activity is moving towards auditory scene analysis, I thought this question very timely. I broke out the problem into two parts, one being at the cochlear level and the other, attention. At the cochlear level, one has to assume that source separation takes place all the time, probably using the criteria of differing F0's for this segregation. Hence, attention is the process of picking a particular source, and here is where the difficulties arise. There could be many factors that could cause a shift in our attention, including an involuntary one if one of the lions was closer to us than the other. From a research viewpoint, I would assume that the first step would be to determine how the cochlear segregates the sources, where the determination of F0's becomes highly critical. My own approach has been documented at my website, www.tonepitch.com and uses a new approach to frequency analysis. The extension of the method towards source segregation requires that I pick not only the most active F0, but a few more in equal or decreasing importance. Assuming that this works, and it should if the source F0's are reasonably well separated, one could then proceed to check what the criteria are that causes involuntary switches in attention. I am sure that a sudden increase in loudness will play an important part. I hope this helps rather than confuse the problem. Cheers, Randy Randhawa > Dear all, > > I have a question of general interest about auditory scene analysis, and > would be grateful for any views on the subject. > > Humans have the remarkable ability to interpret multiple events and > perceive distinct sources within a complex sound environment. The > concept of perceptual streams of information is explained in (Bregman > A.S., Auditory Scene Analysis: The Perceptual Organization of Sound, MIT > Press, 1990). My question is: are we really capable of perceptually > segregating multiple sources concurrently, or are we just focusing our > attention on one source, and then shifting it very quickly to another > source? Evolutionarily speaking, I can see it would be advantageous if > we were being chased by two lions rather than one, to be able to > concentrate on both simultaneously. However, I also have the impression > that if lion 1 roars, we will forget about lion 2 for a moment, and vice > versa. If both roar at the same time, are we now listening to two > separate lions or just a general sound of lions roaring? > In any case, run for it... > > Best, > Mark > >