Subject: Re: perceptual segregation of sound From: Tania Xiao <txiao@xxxxxxxx> Date: Thu, 27 Apr 2006 09:42:30 +1000Hi Mark, I found your question extremely interesting as I have been thinking along a similar strain recently. I am only a newbie postgrad student but based on my limited experiences and music background, I believe that it is most probably a combination of both. I find that when i was a novice musician, when i listened to music (say a Bach Fugue) , it was all a bit of a "formless blob", however as i learnt more and became more of an "expert", top down processes allowed me to segregate and concurrently focus on multiple streams. In terms of your lion example, as i am running away from the lions, i think i would most probably hear the two roars as one big loud alarm telling me to get away as far as possible (i wouldn't really be concerned with which one the sound came out of). However, top-down processes will allow me to realise that the sounds are coming from two lions (perhaps based on the fact that in my "sound dictionary" the roars are louder and a bit more complex compared to what i know about roars coming from just one lion?). So, in a way, initially it is just one big sound but then top down processes influence what i hear based on what i know and thus allow me to "perceive" them as coming from two sources. Once again, this is just my own thoughts on the matter but I am keen to hear what are your and others thoughts about this? cheers, Tania -- Tania Xiao BPsySc(Hons) Research Assistant Ph 3365 7193 School of Psychology and Key Centre of Human Factors University of Queensland Brisbane 4072