A comparison of colour, shape, and flash induced illusory line motion

• Published in: Attention, perception & psychophysics perception & psychophysics, 2017-04, Vol.79 (3), p.911-928
• Main Author: Hamm, Jeff P.
• Format: Article
• Language: English
• Subjects: Adult; Attention; Attention - physiology; Behavioral Science and Psychology; Cognitive Psychology; Color Perception - physiology; Cues; Experiments; Form Perception - physiology; Humans; Individual Differences; Motion; Motion Perception - physiology; Neural networks; Optical Illusions - physiology; Priming; Psychology; Repetition Priming - physiology; Stimuli
• ISSN: 1943-3921; 1943-393X
• DOI: 10.3758/s13414-016-1269-2

When a bar suddenly appears between two boxes, the bar will appear to shoot away from the box that matches it in colour or in shape—a phenomenon referred to as attribute priming of illusory line motion (ILM; colour ILM and shape ILM, respectively). If the two boxes are identical, ILM will still occur away from a box if it changes luminance shortly before the presentation of the bar ( flash ILM). This flash condition has been suggested to produce the illusory motion due to the formation of an attentional gradient surrounding the flashed location. However, colour ILM and shape ILM cannot be explained by an attentional gradient as there is no way for attention to select the matching box prior to the presentation of the bar. These findings challenge the attentional gradient explanation for ILM, but only if it is assumed that ILM arises for the same underlying reason. Two experiments are presented that address the question of whether or not flash ILM is the same as colour ILM or shape ILM. The results suggest that while colour ILM and shape ILM reflect a common illusion, flash ILM arises for a different reason. Therefore, the attentional gradient explanation for flash ILM is not refuted by the occurrence of colour ILM or shape ILM, which may reflect transformational apparent motion (TAM).