Professor Stuart Anstis, Psychology Department, University of California, San Diego

Professor Anstis entertained the crowd at the AVA 2007 Christmas meeting in Aston, UK with his Keynote Lecture and host of illusions using some particularly familiar faces. Amanda Hurrell and Katy Smith were there for the day to chat to customers and record the CRS sponsored lecture which can be viewed again here. Enjoy!

Click here to view the Lecture.

Click the above image to view the slides, and listen to Stuart Anstis’ talk, which was recorded live. The talk is about 20 minutes long. This presentation has been converted into a Flash file and uses streaming technology, so that you can start watching without waiting for the entire file to download. The presentation will open in a new window and run from start to end automatically, or you can use the controls in the top right corner to pause and navigate from slide to slide if you prefer. Don't forget to turn on your speakers!

Having trouble viewing the presentation? Try downloading the latest version of Flash Player by clicking here.

Abstract

Some new(ish) illusions help to understand how we perceive colour, motion and faces. Colour and contours:  Achromatic test contours can materially alter the colours seen in afterimages.  Following adaption to a single multi-coloured coloured plaid, vertical black test lines can elicit afterimages of vertical blue/yellow stripes, while horizontal test lines can elicit afterimages, from the same adapting stimulus, of horizontal red/ green stripes. Conclusion: the visual system averages colours within black/white test contours, and inhibits them laterally across contours. Colour combinations.  One eye viewed a digit OE5¹ in red dots, hidden among green dots, like an Isihara plate.  The other eye viewed a digit OE5¹ in green dots, hidden among red dots.  When these were binocularly fused, the hue discrimination threshold was five times higher for two eyes than for one. So two eyes were worse than one. Motion. Reversed phi, and the Footsteps illusion, reveal the role of luminance and contrast in motion perception.  The Chopsticks and Sliding-Ring illusions demonstrate visual parsing of moving objects.  The Flying Bluebottle measures simultaneous contrast in the motion domain, i.e.induced movement. Faces. Upside-down and negative faces are both hard to recognize.  I used a negative photo of Tony Blair to produce a contrast analog of the Mrs. Thatcher illusion, and a bikini to create a full-body analog.  This tells us about featural versus configural processing of faces and bodies.

Click to read the paper behind the Tony Blair Illusion

Professor Stuart Anstis

Born in England, Dr. Stuart Anstis was a scholar at Winchester and at Corpus Christi College, Cambridge. He took his Ph.D. at Cambridge with Prof. Richard Gregory and went on to teach at the University of Bristol, UK, and at York University, Toronto, Canada.
Since 1991 he has taught at the University of California, San Diego (UCSD). He has been a visiting scientist at the Smith-Kettlewell Institute, San Francisco, the San Francisco Exploratorium, and at IPRI in Japan. He now works in the Psychology Department at UCSD.

Research

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. Has also worked on hearing, including adaptation to frequency-shifted auditory feedback, hearing with the hands, adaptation to gradual change in loudness, and perfect pitch; and on motor aftereffects after jogging on a treadmill.

With George Mather and Frans Verstraten he edited a book on the motion aftereffect . He has given over 250 invited presentations on his research throughout the USA, Europe and Japan, including an invited address in the President's Symposium at the annual meeting of the Society for Neurosciences a few years back and the 1998 Max Wertheimer Lecture in Frankfurt. His work has been featured in Discover magazine (June 1993) and in occasional television programs. He has won awards as an outstanding teacher at York University and at Earl Warren College, UCSD, where he was invited to give the commencement speech to 8000 people at the graduation ceremony in June 1999.

Related Products

ViSaGe Visual Stimulus Generator

Our latest top-of-the-range system is based on 15 years of VSG development. Accurate timing guarantees no dropped or inserted frames; 14 bit DAC output. Now easier than ever to use, with VSG Toolbox for MATLAB.

SpectroCAL

SpectroCAL is an affordable, high-performance spectroradiometer for vision scientists, and makes it extremely simple to measure the Spectral Power Distribution of computer display devices like CRT and LCD monitors.