Visual illusions for film studies

This post contains a number of link to various web sites devoted to visual illusions and some papers on visual illusions that are of interest film researchers. (NB: the papers linked to may not be the final published versions).

Possibly the best site devoted to illusions is Michael Bach’s 87 Optical Illusions and Visual Phenomena, which has an impressive array of very nicely presented illusions. As a researcher on visual perception, Bach has published many papers on how we experience the world including Bach M, Poloschek CM (2006) Optical Illusions, Advances in Clinical Neuroscience and Rehabilitation 6 (2): 20–21, which  provides a short general overview.

George Mather is a researcher at the University of Sussex, who has developed the two-stroke apparent motion illusion, and published on this topic: Mather, G (2006) Two-stroke: a new illusion of visual motion based on the time course of neural responses in the human visual system, Vision Research 46: 2015-2018; and Mather G, Challinor KL (2009) Psychophysical properties of two-stroke apparent motion, Journal of Vision 9 (1): 28.

Other papers on similar illusions are Conway BR, Kitaoka A, Yazdanbakhsh A, Pack CC, Livingstone MS (2005) Neural basis for a powerful static motion illusion, The Journal of Neuroscience 25 (23): 5651-5656; and

Mather’s two-stroke illusion won second place at the ‘Illusion of the Year’ contest in 2005. For information on the other visual illusions, the contest’s web site is here.

Another good site is at the University Of Massachusetts Psychology Department and is maintained by David T. Landrigan.

The wagon-wheel illusion in particular is of interest to film researchers as it raises the question of why we experience motion. (The wagon wheel illusion demonstration at Bach’s website is particularly good). Short-range apparent motion is the traditional explanation for the experience of motion in the cinema:

The illusion of continuous motion is called apparent motion to distinguish it from ‘real’ motion, which is perceived when an object moves continuously across a viewer’s visual field. When Sir Laurence Olivier appears to be fencing in a film, he is in apparent motion, whereas a person walking across the theatre in front the screen is in real motion (Ramachandran & Anstis 1986: 102).

Ramachandran and Anstis’s argument is based on an ontological distinction between ‘real’ motion and ‘apparent’ motion, and that there is a one-to-one correspondence between stimulus and experience. Thus a continuous stimulus results in the experience of ‘real’ motion, while a discrete stimulus results in ‘apparent motion’ (Ramachandran ,V.S., and Anstis, S.M. (1986) The perception of apparent motion, Scientific American 254 (6): 102-109.) But what if our perception is discrete, so that we experience the world as a sequence of snapshots? The one-to-one correspondence between stimulus and experience implied by the ‘real’/’apparent’ distinction is not relevant if all our percepts are discrete, and the ontology of the stimulus (continuous/discrete) is irrelevant to our experience. In simple terms, all our perceptions would be discrete irrespective of the nature of the stimulus, and there would be no difference between watching Olivier on film or someone walking in front of the screen. The viewer would experience motion in the cinema because he experiences motion. This problem is raised in the following papers, most of which cite the cinema as a direct example of discrete perception:

Andrews T, Purves D (2005) The wagon-wheel illusion in continuous light, Trends in Cognitive Sciences 9 (6): 261-263.

Purves D, Paydarfar JA, Andrews TJ (1996) The wagon wheel illusion in movies and reality, Proceedings of the National Academy of Sciences 93 (8): 3693-3697.

van Rullen R, Koch C (2003) Is perception discrete or continuous?, Trends in Cognitive Sciences 7 (5): 207-213.

van Rullen R, Reddy L, Koch C (2005) Attention-driven discrete sampling of motion perception, Proceedings of the National Academy of Sciences 102 (14): 5291-5296.

van Rullen R, Reddy L, Koch C (2006) The continuous wagon wheel illusion is associated with changes in electroencephalogram power at ~13 Hz, The Journal of Neuroscience 26 (2): 502-507.

Van Rullen R, Pascual-Leone A, Batelli L (2008) The continuous wagon wheel illusion and the ‘when’ pathway of the right parietal lobe: a repetitive transcranial magnetic stimulation study, Public Library of Science One 3 (8): e2911.

A challenge to the argument for discrete perception argument in the wagon wheel illusion can be found in Klein K, Holcombe AO, Eagleman DM (2004) Illusory motion reversal is caused by rivalry, not by perceptual snapshots of the visual field, Vision Research 44: 2653-2658; and Klein K, Eagleman DM (2008) Evidence against the temporal subsampling account of illusory motion reversal, Journal of Vision 8 (4): 13.

Yves Gallifret deals with the history of retinal persistence and cinema in an English language essay from Comptes Rendues Biologies: Gallifret Y (2006) Visual persistence and cinema?, Compte Rendues Biologies 329 (5-6): 369-385.

An article on a similar subject is Paul St. George’s piece on chronophotography: St. George, P (2009) Using chronophotography to replace Persistence of Vision as a theory for explaining how animation and cinema produce the illusion of continuous motion, Animation Studies 4: 17-26.

About Nick Redfern

I am an independent academic with over 15 years experience teaching film in higher education in the UK. I have taught film analysis, film industries, film theories, film history, science fiction at Manchester Metropolitan University, the University of Central Lancashire, and Leeds Trinity University, where I was programme leader for film from 2016 to 2020. My research interests include computational film analysis, horror cinema, sound design, science fiction, film trailers, British cinema, and regional film cultures.

Posted on May 6, 2010, in Cognitive Film Theory, Film Studies, Film Theory, Visual illusions and tagged , , , , . Bookmark the permalink. 3 Comments.

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