The role of the saccade target object in the perception of a visually stable world.
Although the proximal stimulus shifts position on our retinae with each saccade, we perceive our world as stable and continuous. Most theories of visual stability implicitly assume a mechanism that spatially adjusts perceived locations associated with the retinal array by using, as a parameter, extra-retinal eye position information, a signal that encodes the size and direction of the saccade. The results from the experiment reported in this article challenge this idea. During a participant's saccade to a target object, one of the following was displaced: the entire scene, the target object, or the background behind the target object. Participants detected the displacement of the target object twice as frequently as the displacement of the entire background. The direction of displacement relative to the saccade also affected detectability. We use a new theory, the saccade target theory (McConkie & Currie, 1996), to interpret these results. This theory proposes that retinal (as opposed to extra-retinal) factors, primarily those concerning the saccade target object, are critical for the detection of intrasaccadic stimulus shifts.
Currie
C B
CB
Beckman Institute for Advanced Science and Technology, University of Illinois, Urbana-Champaign, USA. fantasticks@netscape.net
McConkie
G W
GW
Carlson-Radvansky
L A
LA
Irwin
D E
DE
D005403:Fixation, Ocular / Q000502:physiology; D006801:Humans; D011930:Reaction Time; D012160:Retina / Q000502:physiology; D012438:Saccades / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology*