I'm wondering if observing it in the mirror was the cause of the illusion. (Especially if the mirror was a polarized one???) Beth Benoit ----- Original Message ----- From: "Stephen Black" <[EMAIL PROTECTED]> To: "Teaching in the Psychological Sciences" <[EMAIL PROTECTED]> Sent: Wednesday, April 07, 2004 5:17 PM Subject: Wagon-wheel illusion again
> Just recently we were discussing the wagon-wheel illusion, and if I > recall correctly, both Tom Alloway's students and Beth Benoit > reported seeing the phenomenon under steady illumination while > driving down the highway. > > By coincidence, there's a report just out (well, I just spotted it > anyway) investigating the phenomenon. They say it doesn't occur under > steady illumination under laboratory conditions. So students of Tom > and Beth, science says you didn't see what you saw. I append the > abstract below. It has the distinction of coming from theoretical > physicists and from Iran, a rather unusual source on both counts, it > seems to me. > > If I may speculate on the discrepancy between what science found and > what people experienced, I wonder if under real-life conditions such > as driving down the highway, what appears to be steady illumination > may actually be flickering. For example, if the light illuminating > the wheels was interrupted by trees or by posts along the highway, it > would flicker, and so understandably cause the effect. I seem to > recall that epileptic seizures have been triggered in susceptible > individuals by such flickering when driving down a road lined with > trees. > > Stephen > > Perception. 2003;32(11):1307-10. > Wagon-wheel illusion under steady illumination: real or illusory? > Pakarian P, Yasamy MT. > > School of Intelligent Systems, Institute for Studies in Theoretical > Physics and Mathematics (IPM), Niavaran Square, Tajrish, Tehran, PO > Box 19395-5746, Iran. [EMAIL PROTECTED] > > Wheels turning in the movies sometimes appear to rotate backwards. > This is called the wagon-wheel illusion (WWI). The mechanism of this > illusion is based on the intermittent nature of light in films and > other stroboscopic presentations, which renders them as a series of > snapshots rather than a continuous visual data stream. However, there > have been claims that this illusion is seen even in continuous light, > which would suggest that the visual system itself may sample a > continuous visual data stream. We examined the rate of this putative > sampling and its variations across individuals while in different > psychological states. We obtained two results: (i) WWI occurred in > stroboscopic lights as expected, (ii) WWI was never reported by our > subjects under continuous lights, such as sunlight and lamps with DC > power source. Thus, WWI cannot be taken as evidence for discreteness > of conscious visual perception. > ___________________________________________ > Stephen L. Black, Ph.D. tel: (819) 822-9600 ext 2470 > Department of Psychology fax: (819) 822-9661 > Bishop's University e-mail: [EMAIL PROTECTED] > Lennoxville, QC J1M 1Z7 > Canada > > Dept web page at http://www.ubishops.ca/ccc/div/soc/psy > TIPS discussion list for psychology teachers at > http://faculty.frostburg.edu/psyc/southerly/tips/index.htm > _______________________________________________ > > > --- > You are currently subscribed to tips as: [EMAIL PROTECTED] > To unsubscribe send a blank email to [EMAIL PROTECTED] > --- You are currently subscribed to tips as: [EMAIL PROTECTED] To unsubscribe send a blank email to [EMAIL PROTECTED]
