Subject: another octave illusion article From: Ranil Sonnadara <ranil(at)PSYCHOLOGY.MCMASTER.CA> Date: Wed, 10 Nov 2004 09:42:50 -0500Dear list, Since there seems to be some interest in the octave illusion at the moment... I would like to announce another in-press article on the octave illusion titled "Perceived intensity effects in the octave illusion", which will appear in Perception and Psychophysics. In this article, we report an intensity component to the illusion which has not previously been discussed, and show that it depends on the sequential nature of the illusion-eliciting stimulus. The abstract is pasted below. I am happy to send out a PDF version of the article to anyone interested. sincerely, Ranil Sonnadara "Perceived intensity effects in the octave illusion". Sonnadara, R.R. and Trainor, L.J. We show that there is an intensity aspect to the Octave Illusion in addition to the pitch and location aspects originally reported by Deutsch (1974). In Experiment 1, we ask participants to directly compare the stimulus giving rise to the illusion (ILLU) with one mimicking its most commonly reported percept (IC) and show that they are easily able to distinguish between the two. In Experiment 2 we show that there is a clear difference in the perceived loudness of ILLU and IC when IC follows ILLU, but not when IC precedes ILLU. In Experiments 3 and 4, we show that this effect depends on the alternation of high and low tones between the ears in an extended pattern. In Experiment 5, we show that this difference in perceived loudness disappears if the interval between the ILLU and IC stimuli is sufficiently large. We conclude that there is a previously unreported intensity component to the octave illusion, in addition to the pitch and location components.