Depth Adjacency and Induced Motion

Walter C. Gogel; Peter J. Mac Cracken

doi:10.2466/pms.1979.48.2.343

Depth Adjacency and Induced Motion

Perceptual and Motor Skills ◽

10.2466/pms.1979.48.2.343 ◽

1979 ◽

Vol 48 (2) ◽

pp. 343-350 ◽

Cited By ~ 29

Author(s):

Walter C. Gogel ◽

Peter J. Mac Cracken

Keyword(s):

Test Object ◽

Induced Motion ◽

Adjacency Principle

Induced motion was investigated as a function of the stereoscopic separation of the test and inducing object and the instructions to attend to or to ignore the inducing object. It was found that stereoscopically displacing the test object from the inducing object with both kinds of instructions resulted in a decrease in the magnitude of induction particularly with crossed disparity. These results are consistent with the adjacency principle and with the ability of attention as well as adjacency to modify the magnitude of the induced motion.

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Measuring Attention Using Induced Motion

Perception ◽

10.1068/p180303 ◽

1989 ◽

Vol 18 (3) ◽

pp. 303-320 ◽

Cited By ~ 48

Author(s):

Walter C Gogel ◽

Thomas J Sharkey

Keyword(s):

Apparent Motion ◽

Test Object ◽

The Other ◽

Horizontal Motion ◽

Involuntary Attention ◽

Frontoparallel Plane ◽

Physical Motion ◽

Test Spot ◽

Induced Motion

Attention was measured by means of its effect upon induced motion. Perceived horizontal motion was induced in a vertically moving test spot by the physical horizontal motion of inducing objects. All stimuli were in a frontoparallel plane. The induced motion vectored with the physical motion to produce a clockwise or counterclockwise tilt in the apparent path of motion of the test spot. Either a single inducing object or two inducing objects moving in opposite directions were used. Twelve observers were instructed to attend to or to ignore the single inducing object while fixating the test object and, when the two opposing inducing objects were present, to attend to one inducing object while ignoring the other. Tracking of the test spot was visually monitored. The tilt of the path of apparent motion of the test spot was measured by tactile adjustment of a comparison rod. It was found that the measured tilt was substantially larger when the single inducing object was attended rather than ignored. For the two inducing objects, attending to one while ignoring the other clearly increased the effectiveness of the attended inducing object. The results are analyzed in terms of the distinction between voluntary and involuntary attention. The advantages of measuring attention by its effect on induced motion as compared with the use of a precueing procedure, and a hypothesis regarding the role of attention in modifying perceived spatial characteristics are discussed.

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