The line–motion illusion: Attention or impletion?

Abstract

When a brief lateral cue precedes an instantaneously presented horizontal line, observers report a sensation of motion in the line propagating from the cued end toward the uncued end. This illusion has been described as a measure of the facilitatory effects of a visual attention gradient (O. Hikosaka, S. Miyauchi, & S. Shimqjo, 1993a). Evidence in the present study favors, instead, an account in which the illusion is the result of an impletion process that fills in interpolated events after the cue and the line are linked as successive states of a single object in apparent motion.Over the past 20 years or so, a large body of research has provided a picture of visual attention as a flexible, mobile source of processing facilitation that can be directed intentionally or summoned involuntarily by stimuli in the environment (Nakayama & Mackeben, 1989;Posner, 1980;Yantis & Jonides, 1984). One characteristic typically attributed to attention is its acceleration of the processing of visual stimuli. For example, in the paradigm developed by Posner (1980), participants make a speeded response to a target that can appear either to the left or to the right of fixation. When the target location is precued by a brief flash, participants are faster to respond than when the precue gives no advance information about the target location, even though fixation remains central. When the target occurs in the noncued location, responses are slowed. The difference in performance between these two conditions has been taken as a measure of the effects (both costs and benefits) of focal visual attention. Laberge (1983) found evidence for a gradient of attention, with the degree of facilitation decreasing as a function of distance from the center of the attended area.Recently, another phenomenon has been proposed to demonstrate the facilitatory effects of attention (Hikosaka,

The duration of 3-D form analysis in transformational apparent motion

“…For example, when the stimulus configuration shown in Figure 10, Image 1, is replaced all at once by Image 2a, motion inward from both the left-hand cue and the right-hand cue is perceived. However, if Image 1 is replaced all at once by Image 2b instead of Image 2a (Tse et al, 1996(Tse et al, , 1998; see also Downing & Treisman, 1997), then the percept between the cues is very different. Now the line between the cues undergoes TAM entirely away from the left-hand cue.…”

“…According to their model, when the initial spot appears, an attentional gradient forms around the spot; when the line appears all at once, portions of the line nearer the attended spot enter a motion detecting mechanism before portions of the line that lay farther away from the attended location. Other authors (Downing & Treisman, 1995, 1997Kawahara, Yokosawa, Nishida, & Sato, 1996;Tse & Cavanagh, 1995;Tse, Cavanagh, & Nakayama, 1996, using more complex first and second image shapes, challenged the attentional prior entry account. They argued instead that illusory line motion was actually a variant of translational apparent motion (e.g., Anstis, 1980;Braddick, 1980;Dawson, 1991;Wertheimer, 1912Wertheimer, /1961.…”

Does attention cause illusory line motion?

“…However, perhaps a weak ILM experience is generated by endogenous cues but the real line drawing and strong ILM generated from the peripheral cues produced such strong motion experiences that any endogenously generated ILM was, by comparison, overwhelmed. Indeed, some previous studies that reported ILM induced by endogenous orienting also reported effects smaller than those found with exogenous orienting (P. E. Downing & Treisman, 1997;Schmidt, 2000). We tested this "adaptation level" possibility in Experiment 3 by never presenting a strong line motion perception within the context of the experiment.…”

“…One leading explanation for the illusion (Hikosaka, Miyauchi, & Shimojo, 1993a, 1993bSchmidt & Klein, 1997) is based on the idea that there is a gradient of accelerated arrival times at perceptual levels of processing around a cued location and that, when a line is presented (all at once) across this gradient, the difference in arrival times across the line is interpreted by motion perception systems as a drawing of the line over time. Although there are some notable exceptions to this view (e.g., P. E. Downing & Treisman, 1997;Tse & Cavanagh, 1995), it does serve as a general framework for the research presented here.…”

“…This nonveridical perception-which has been so strong that in human subjective experience (Christie & Barresi, 2002) and cat visual cortex (Jancke, Chavane, Naaman, & Grinvald, 2004) it is indistinguishable from real motion-has been referred to as illusory line motion (ILM). 1 There have been numerous studies of the illusion that extend the original observation and seek to understand its source and nature (Downing & Treisman, 1997;Schmidt, 2000). One leading explanation for the illusion (Hikosaka, Miyauchi, & Shimojo, 1993a, 1993bSchmidt & Klein, 1997) is based on the idea that there is a gradient of accelerated arrival times at perceptual levels of processing around a cued location and that, when a line is presented (all at once) across this gradient, the difference in arrival times across the line is interpreted by motion perception systems as a drawing of the line over time.…”