Perceptual emphasis of visual field meridians modulates the object-based attention shift direction anisotropy
Mentor 1
Adam S. Greenberg
Location
Union Wisconsin Room
Start Date
27-4-2018 1:00 PM
Description
Object-based attention (OBA) serves to prioritize attended objects over unattended objects. Our previous research showed that shifting attention across the visual field meridians is more efficient horizontally than vertically (i.e., Shift Direction Anisotropy; SDA), and suggests that the meridians play a critical modulatory role in the orienting of OBA. Our goal here was to causally implicate the meridians by manipulating their perceptual visibility to determine whether “meridian emphasis” impacts the SDA. Participants were presented a gray L-shaped object composed of a horizontal and vertical rectangle joined together at a 90-degree angle on a black background. Following a spatial cue at the object vertex, a target (‘T’) appeared at either the cued location (“valid”) or at one of two non-cued locations equidistant from the cue in the horizontal (“invalid-horizontal”) or the vertical (“invalid-vertical”) component rectangle. Non-target letters (‘L’) appeared as placeholders at the two non-target locations. Participants performed a detection task and RTs were recorded. Horizontal and vertical meridian perceptual visibility was emphasized by placing white visible lines on the meridians (Experiment 1) and creating illusory contours at the meridians (Experiment 2). In Experiment 1 (N=28), a significant SDA (~69 ms) was found when the vertical meridian was emphasized, but not when the horizontal meridian was emphasized. In Experiment 2 (N=14), a significant SDA was found when the vertical meridian was emphasized (~80 ms) as well as when the horizontal meridian was emphasized (~64 ms). Together, these results show that emphasizing the perceptual visibility of the horizontal meridian can selectively eliminate the SDA by reducing competition for attentional resources along the vertical meridian, depending on the strength of the meridian emphasis. These data suggest that object-based attention is sensitive to strong manipulations of the meridians, but not weaker ones.
Perceptual emphasis of visual field meridians modulates the object-based attention shift direction anisotropy
Union Wisconsin Room
Object-based attention (OBA) serves to prioritize attended objects over unattended objects. Our previous research showed that shifting attention across the visual field meridians is more efficient horizontally than vertically (i.e., Shift Direction Anisotropy; SDA), and suggests that the meridians play a critical modulatory role in the orienting of OBA. Our goal here was to causally implicate the meridians by manipulating their perceptual visibility to determine whether “meridian emphasis” impacts the SDA. Participants were presented a gray L-shaped object composed of a horizontal and vertical rectangle joined together at a 90-degree angle on a black background. Following a spatial cue at the object vertex, a target (‘T’) appeared at either the cued location (“valid”) or at one of two non-cued locations equidistant from the cue in the horizontal (“invalid-horizontal”) or the vertical (“invalid-vertical”) component rectangle. Non-target letters (‘L’) appeared as placeholders at the two non-target locations. Participants performed a detection task and RTs were recorded. Horizontal and vertical meridian perceptual visibility was emphasized by placing white visible lines on the meridians (Experiment 1) and creating illusory contours at the meridians (Experiment 2). In Experiment 1 (N=28), a significant SDA (~69 ms) was found when the vertical meridian was emphasized, but not when the horizontal meridian was emphasized. In Experiment 2 (N=14), a significant SDA was found when the vertical meridian was emphasized (~80 ms) as well as when the horizontal meridian was emphasized (~64 ms). Together, these results show that emphasizing the perceptual visibility of the horizontal meridian can selectively eliminate the SDA by reducing competition for attentional resources along the vertical meridian, depending on the strength of the meridian emphasis. These data suggest that object-based attention is sensitive to strong manipulations of the meridians, but not weaker ones.
