When a straight, rigid line segment is put into certain types of motion, it appears to an observer to lose its rigidity and become rubbery, as in the well-known “rubber pencil illusion.“ The factors controlling this illusion were examined, including the nature of the motion employed (harmonic or linear oscillation), the amplitudes of the translational and rotational components of the motion, and the phase relationship between these two components. The effect is shown to be due to visual persistence. The status of the illusion as a potential counterexample to the rigidity principle (that moving, two-dimensional arrays will be perceived as rigid) is discussed.
Burr, D. Motion smear.Nature, 1980,284, 164–165.
Gilbert, G., &Rydell, W.Great tricks of the master magicians. New York: Golden Press, 1977.
Goldstein, E. B.Sensation and perception. Belmont, Calif: Wadsworth, 1980.
Hochberg, J. E.Perception (2nd ed.). Englewood Cliffs, N.J: Prentice-Hall, 1978.
Johansson, G. Visual perception of rotary motion as transformation of conic sections.Psychologia, 1974,17, 226–237.
Johansson, G. Visual motion perception.Scientific American, 1975,232, 76–88.
Long, G. M. Iconic memory: A review and critique of the study of short-term visual storage.Psychological Bulletin, 1980,118, 785–820.
Ullmas, S.The interpretation of visual motion. Cambridge, Mass: M.I.T. Press, 1979.
Wallach, H., &O’Connell, D. N. The kinetic depth effect.Journal of Experimental Psychology, 1953,45,205–217.
This research was supported in part by Research Development and Incentive Funds from the Research Foundation of SUNY.
About this article
Cite this article
Pomerantz, J.R. The rubber pencil illusion. Perception & Psychophysics 33, 365–368 (1983). https://doi.org/10.3758/BF03205883
- Phase Angle
- Linear Motion
- Rotational Component
- Harmonic Motion
- Visual Persistence