I don't think that there is a single/simple explanation. However, my preference is to think of it as an example of the hypothesis-testing nature of perception. That is, many stimuli are open to multiple interpretations (e.g., multistable images, such as Rubin's face/vase illusion or the old lady/young girl figure). When faced with such ambiguity, our visual systems don't seize and hold a single interpretation, but continue to try out alternative explanations-- which will often cause a change in interpretation. I think that anyone who looks at that rotating figure long enough will see a shift in direction of rotation. You can find other examples, such as the rotating ferris wheel.
http://www.skidmore.edu/%7Ehfoley/PercLabs/Color&Motion.htm <scroll down to the bottom of #12> There was also a neat example provided by Gilbert, S. (1991) A new kinetic depth illusion..., ToP, 18, 55-56. With a simple BASIC program, Gilbert showed how you could get an illusion of depth, but then the helix-like structure would reverse direction of rotation as you watched it. Cool stuff! Hugh On Feb 5, 2008, at 11:45 AM, Larry Daily wrote: > > Friends, > > One of my colleagues here forwarded the attached image file to me > and asked if I could explain why the dancer is sometimes seen as > spinning to the left and sometimes to the right. I don't buy the > left brain/right explanation that came with it, but I have no real > idea why it works. Can anyone help me out? > > Thanks, > Larry > > ************************************************************ > Larry Z. Daily > Associate Professor of Psychology > Psychology Department Chair > > Department of Psychology > White Hall, Room 216 > Shepherd University > Shepherdstown, West Virginia 25443 > > Psychology phone: (304) 876-5297 > > email: [EMAIL PROTECTED] > WWW: http://webpages.shepherd.edu/LDAILY/index.html > > Adam's prize was open eyes > His sentence was to see > - The Dreamer > - Tom Rush > > > -------------------------------------------------- Hugh J. Foley Department of Psychology Skidmore College Saratoga Springs, NY 12866 518-580-5308 http://www.skidmore.edu/~hfoley -------------------------------------------------- "And I still don't know if I'm a falcon, a storm, or an unfinished song." Rilke -------------------------------------------------- --- To make changes to your subscription contact: Bill Southerly ([EMAIL PROTECTED])
