Thanks to all who tried to help me understand the relationship between backward wheel-spinning and persistence of vision, the phi phenomenon, etc. It will take me awhile to sift through all of the posts and e-mail and figure out what to make of the information. So many different responses, some claiming that persistence of vision, as it has been conventionalized by film studies, has been disproved, some have claimed that the back-spinning wheel has nothing to do with retinal response per se but more to do with the stroboscopic effect of the phi phenomenon...and more. To tell y'all the truth, I'm not sure quite what to think or believe...many of the responses contradict one another...though all have provided me with much brain food to munch on for awhile. I guess I need to re-think how I might go about presenting this material to an audience. Clearly I need a better model than the one I have been using...or I could keep it simple and make many disclaimers? I notice that Bordwell and Thompson don't even use the term "persistence of vision" in their updated FILM HISTORY textbook. I wonder if the deletion is deliberate, based on fairly recent reconsiderations of our models of perception? In any case, thanks for problematizing the construct.... What is most interesting to me is how elusive a uniform and consistent "scientific" explanation seems to be...or am I defaulting to a sort of convenient postmodern posture...? I can't tell any more. It must be spring break. Meryem Ersoz University of Oregon ---- To signoff SCREEN-L, e-mail [log in to unmask] and put SIGNOFF SCREEN-L in the message. Problems? Contact [log in to unmask]