Abstract
Five experiments examined the time taken to judge that two consecutive elongated geometrical shapes had the same structure, irrespective of their orientation. Shape transformations either changed the orientation of the principal axis while maintaining the relative locations of focal features or maintained the orientation of the principal axis while changing the relative locations of focal features, or they changed both. Experiment 1 demonstrated that changes in the orientation of the principal axis were more detrimental to matching than were changes in the locations of the shape’s focal features. Indeed, the time taken to match same-orientation shapes was the same as that taken to match shapes that maintained the same position in the visual field. Further experiments showed that this result was not due to differential apparent motion in the transformation conditions, that it was not due to response bias, and that it generalized across shapes. However, the result was different when subjects could predict the location of the to-be-matched stimulus. In this case, performance was principally affected by the position of the focal feature of the shape and not by the shape’s orientation. It is suggested that the results reflect the efficiency with which subjects can construct matching representations for the stimuli When subjects cannot predict stimulus locations, they generate representations by describing shape structure relative to the shape’s principal axis. When the axis of the to-be-matched shapes is constant, subjects can use the same procedure in generating this representation for both shapes, facilitating matching relative to the case in which the orientation of the axis changes. When subjects can predict the stimulus location, they selectively attend to the focal features of shapes, minimizing the effects of shape orientation.
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Bamber, D. (1969). Reaction times and error rates for “same-different” judgments of multidimensional stimuli.Perception & Psychophysics,6, 169–174.
Beck, J. (1972). Similarity grouping and peripheral discriminability under uncertainty.American Journal of Psychology,85, 1–20.
Bevan, M. F., Denton, J. Q., &Myers, J. L. (1974). The robustness of the F test to violations of continuity and form of treatment population.British Journal of Mathematical and Statistical Psychology,27, 199–204.
Braddick, O. (1974). A short-range process in apparent motion.Vision Research,14, 519–527.
Braine, L. G. (1978). A new slant on orientation perception.American Psychologist,33, 10–22.
Braine, L. G., Relyea, L., &Davidman, L. (1981). On how adults identify the orientation of a shape.Perception & Psychophysics,29, 138–144.
Bundesen, C., &Larsen, A. (1975). Visual transformation of size.Journal of Experimental Psychology: Human Perception andPerformance,1, 214–220.
Cooper, L. A., &Shepard, R. N. (1973). Chronometric studies of the rotation of mental images. In W. G. Chase (Ed.),Visual information processing. New York: Academic Press.
Cooper, L. A., &Shepard, R. N. (1975). Mental transformations in the identification of left and right hands.Journal of Experimental Psychology: Human Perception and Performance,1, 221–230.
Eriksen, C. W., O’Hara, W. P., &Eriksen, B. A. (1982). Response competition effects insame-different judgments.Perception & Psychophystcs,32, 261–270.
Goldmeier, E. (1936). Uber Ahnlichkeit be: gesehenen Figuren.Psychologische Forschung,21, 146–208.
Hinton, G. E. (1981). A parallel computation that assigns canonical object-based frames of reference. InProceedings of the Seventh International Joint Conference on Artificial Intelligence (Vancouver, B.C., Canada).
Hinton, G. E., &Parsons, L. M. (1981). Frames of reference and mental imagery. In J. Long & A. Baddeley (Eds.),Attention and performance IX. Hillsdale, NJ: Erlbaum.
Humphreys, G. W. (1983). Reference frames and shape perception.Cognitive Psychology,15, 151 - 196.
Julesz, B. (1971).Foundations of cyclopean perception. Chicago: University of Chicago Press.
Julesz, B., Gilbert, E. N., Shepp, L. A., &Frisch, H. L. (1973). Inability of humans to discriminate between visual textures that agree in second-order statistics-revisited.Perception,2, 391–405.
Kolers, P. A. (1972).Aspects of motion perception. New York: Pergamon.
Krueger, L. (1978). A theory of perceptual matching.Psychological Review,115, 278–304.
Krueger, L. E., &Shapiro, R. G. (1981). A reformulation of Proctor’s unified theory for matching-task phenomena.Psychological Review,811, 573–581.
Larsen, A., &Bundesen, C. (1978). Size scaling in visual pattern recognition.Journal of Experimental Psychology: Human Perception and Performance,4, 1–20.
Lockhead, G. R. (1972). Processing dimensional stimuli: A note.Psychological Review,79, 410–419.
Mach, E. (1897).Contributions to the analysis of sensations. Chicago: Open Court.
Marr, D. (1979). Representing and computing visual information. In P. H. Winston & R. H. Brown (Eds.),Artificial intelligence: An MIT perspective (Vol. 2). London: MIT Press.
Marr, D. (1980). Visual information processing: The structure and creation of visual representations.Philosophical Transactions of the Royal Society (London), B,290, 199–218.
Marr, D. (1982).Vision. San Francisco: Freeman.
Marr, D., &Nishihara, H. K. (1978). Representation and recognition of the spatial organisation of three-dimensional shapes.Proceedings of the Royal Society (London), B,200, 269–294.
Metzler, J., &Shepard, R. N. (1974). Transformational studies of the internal representation of three-dimensional objects. In R. Solso (Ed.),Theories in cognitive psychology: The Loyola symposium. Potomac, MD: Erlbaum.
Proctos, R. W. (1981). A unified theory for matching-task phenomena.Psychological Review,88, 291–326.
Proctor, R. W., &Rao, K. V. (1983). Null effects of exposure duration and heterogeneity of difference on thesame-different disparity in letter matching.Perception & Psychophysics,33, 163–171.
Rock, I., DiVita, J., &Barbeito, R. (1981). The effect on form perception of change of orientation in the third dimension.Journal of Experimental Psychology: Human Perception and Performance,7, 719–732.
Rock, I., &Leaman, R. (1963). An experimental analysis of visual symmetry.Acta Psychologia,21, 171–183.
Sekuler, R., &Nash, D. (1972). Speed of size scaling in human vision.Psychonomic Science,27, 93–94.
Shepard, R. N. (1975). Form, formation, and transformation of internal representations. In R. Solso (Ed.),Information processing and cognition: The Loyola symposium. Hillsdale: NJ: Erlbaum.
Shepard, R. N., &Metzler, J. (1971). Mental rotation of three-dimensional objects.Science,171, 701–703.
Yin, R. K. (1969). Looking at upside down faces.Journal of Experimental Psychology,81, 141–145.
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This work was supported by a grant from the Social Science Research Council. I would like to thank Penny Wilcox for her help in producing the presentation programs, Philip Quinlan and Jane Riddoch for their discussion of earlier drafts of this paper, and an anonymous referee for helpful comments during its processing.
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Humphreys, G.W. Shape constancy: The effects of changing shape orientation and the effects of changing the position of focal features. Perception & Psychophysics 36, 50–64 (1984). https://doi.org/10.3758/BF03206353
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DOI: https://doi.org/10.3758/BF03206353