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School Seminar Series

School Seminar Series
3:00pm Friday, 10th July 2009
4:00pm Friday, 10th July 2009

The School are pleased to announce that  Prof. Stuart Anstis will present a 
talk titled "Eight Illusions of Colour & Motion"

Professor Anstis is one of the worlds most influential vision 
scientists. In additional to his considerable empirical achievements, 
Prof. Anstis has been an inspiration to numerous budding vision 
scientists, instilling a sense of excitement, wonder and humor in all 
who have had the good fortune to listen to his talks. He completed his 
Ph.D. at Cambridge under the guidance of Prof. Richard Gregory and 
since 1991 has taught at the University of California, San Diego 
(UCSD). He has published about 120 papers on visual perception, 
including the perception of real and apparent motion, Pulfrich's 
Pendulum, movement aftereffects, contingent aftereffects, coloured 
afterimages, normal and defective colour vision in babies, adaptation 
to gradual change in luminance, and the apparent size of holes felt 
with the tongue. He has given over 250 invited presentations on his 
research throughout the USA, Europe, Japan, and now in Brisbane 


NOTE: We have booked a special room for this occasion. The chance to 
host Prof. Anstis only opened up at the last minute, and so we are 
announcing this talk at the earliest opportunity. The room may be 
subject to change, but please set aside this time slot on Friday, as 
Prof. Anstis will definitely be gracing us with his presence at this 

I shall demonstrate some new illusions: 1. Colour: Black/white 
contours and coloured contours can interact. Coloured afterimages on a 
white test field are strengthened if a black line is drawn around 
them. We used this fact to produce colour filling-in, in which colors 
are subjectively averaged between, bur never across,luminance 
contours. As a result, a given point within a colored pattern can have 
different subjective hues at different times. We also show how 
adaptation to black/white horizontal or vertical lines can alter the 
perceived colour of a test pattern. This suggests that double-duty 
neural units are tuned to both colour and orientation. 2. Induced 
Motion. When a bug flies round and round along a circular path, a 
moving background can make its path look larger, or smaller, or like a 
tall thin ellipse, or a short wide ellipse. 3. Zigzag motion: A field 
of sparse random dots makes small jumps to the right, alternating with 
large jumps downward, so its path describes a steep staircase. The 
perceived direction depends upon viewing distance. From far off, the 
dots appear to move down; and from close up, the same dots appear to 
move to the right. Motion aftereffects can be produced in unexpected 
directions. 4. Motion shifts: Motion can shift the perceived position 
of nearby stationary objects.

Accessed: 2489 times
Created: Monday, 6th July 2009 by windowl
Modified: Monday, 23rd November 2009 by windowl
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