Effects of stimulus material on the Fröhlich illusion

• Published in: Vision research (Oxford) Vol. 42; no. 2; pp. 181 - 189
• Main Authors: Kerzel, Dirk, Müsseler, Jochen
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 2002; Elsevier Science
• Subjects: Adult; Analysis of Variance; Attention; Biological and medical sciences; Fundamental and applied biological sciences. Psychology; Humans; Illusion; Localization; Motion; Motion Perception; Optical Illusions; Perception; Photic Stimulation - methods; Psychology. Psychoanalysis. Psychiatry; Psychology. Psychophysiology; Rotation; Space perception; Vision; Motion; Illusion; Space perception; Localization; Attention; Human; Stimulus localization; Stimulus movement; Vision; Optical illusion; Experimental study; Visual attention; Stimulus position
• ISSN: 0042-6989; 1878-5646
• DOI: 10.1016/S0042-6989(01)00271-1

In the Fröhlich illusion, judgements of the first position of a moving object are typically displaced in the direction of motion. The illusion has been obtained with linear motion of a small target, and with rotary motion of a spatially extended line. We compared judgements of the initial orientation of a small dot and a line that rotated around the point of fixation. The illusion was absent with the dot, whereas it was reliably obtained with the line. When the density of the line was reduced to two dots, the illusion persisted. However, the illusion was absent when a half-line extending to only one side from fixation was presented. We discuss the results with respect to two attentional accounts of the Fröhlich illusion and an account based on spatiotemporal integration.