September 2015
Volume 15, Issue 12
Free
Vision Sciences Society Annual Meeting Abstract  |   September 2015
The influence of attention on contrast perception, contrast discrimination, and saccadic reaction time.
Author Affiliations
  • Madhumitha Mahadevan
    College of Optometry,University of Houston
  • Harold Bedell
    College of Optometry,University of Houston
  • Scott Stevenson
    College of Optometry,University of Houston
Journal of Vision September 2015, Vol.15, 1259. doi:10.1167/15.12.1259
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      Madhumitha Mahadevan, Harold Bedell, Scott Stevenson; The influence of attention on contrast perception, contrast discrimination, and saccadic reaction time.. Journal of Vision 2015;15(12):1259. doi: 10.1167/15.12.1259.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract

Visual spatial attention can increase contrast sensitivity and decrease manual or saccade reaction times (SRTs) in attended compared to unattended locations. Because stimulus contrast also influences SRTs, we asked whether an enhancement of suprathreshold contrast can account for the decrease in SRTs with valid cueing. This study used a dual task paradigm that assessed both perceived contrast and SRTs to targets with various physical contrasts. The subjects (N = 3) were presented with a central fixation target, which also carried an endogenous cue (an arrow) to an upcoming peripheral target’s direction but not its eccentricity. The cue was 75% valid, 12.5% invalid and 12.5% neutral. A circular grating (angular size of 1 degree with 8 cpd) of a standard suprathreshold contrast was flashed at fixation, followed by a circular grating flashed peripherally at 1 of 13 suprathreshold contrasts for 8 ms (1 frame). Subjects were to saccade to the location where the peripheral target flashed and to respond if the target’s contrast appeared to be higher or lower than the preceding central standard. The results exhibit a robust reduction of SRTs with valid cueing, but the peripheral contrast that the subjects judged equal to the central standard did not differ significantly across cueing conditions. The results are not consistent with an attention-induced contrast enhancement for targets of suprathreshold contrast. The cue-related reduction of SRTs to suprathreshold targets may reflect a direct influence of attention on motor programming.

Meeting abstract presented at VSS 2015

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