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Journal of the Optical Society of America A

Journal of the Optical Society of America A


  • Vol. 20, Iss. 7 — Jul. 1, 2003
  • pp: 1341–1355

Saccadic and perceptual performance in visual search tasks. I. Contrast detection and discrimination

Brent R. Beutter, Miguel P. Eckstein, and Leland S. Stone  »View Author Affiliations

JOSA A, Vol. 20, Issue 7, pp. 1341-1355 (2003)

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Humans use saccadic eye movements when they search for visual targets. We investigated the relationship between the visual processing used by saccades and perception during search by comparing saccadic and perceptual decisions under conditions in which each had access to equal visual information. We measured the accuracy of perceptual judgments and of the first search saccade over a wide range of target saliences [signal-to-noise ratios (SNRs)] in both a contrast-detection and a contrast-discrimination task. We found that saccadic and perceptual performances (1) were similar across SNRs, (2) showed similar task-dependent differences, and (3) were well described by a model based on signal detection theory that explicitly includes observer uncertainty [M. P. Eckstein et el., J. Opt. Soc. Am. A 14, 2406 (1997)]. Our results demonstrate that the accuracy of the first saccade provides much information about the observer’s perceptual state at the time of the saccadic decision and provide evidence that saccades and perception use similar visual processing mechanisms for contrast detection and discrimination.

© 2003 Optical Society of America

OCIS Codes
(330.1880) Vision, color, and visual optics : Detection
(330.2210) Vision, color, and visual optics : Vision - eye movements
(330.4060) Vision, color, and visual optics : Vision modeling
(330.4300) Vision, color, and visual optics : Vision system - noninvasive assessment

Brent R. Beutter, Miguel P. Eckstein, and Leland S. Stone, "Saccadic and perceptual performance in visual search tasks. I. Contrast detection and discrimination," J. Opt. Soc. Am. A 20, 1341-1355 (2003)

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  61. This definition compares human- and ideal-observer performances at the same SNR. As suggested by a reviewer, it is also possible to define efficiency as a comparison between the human- and ideal-observer SNRs required to achieve the same performance level. In this alternative definition, efficiency is equal to (SNR ideal /SNR human)2. The two definitions are equivalent if human d is directly proportional to SNR (uncertainty is equal to zero), as is the case for our discrimination task. They are not the same for nonzero uncertainty (nonzero intercept), as is the case for our detection task.

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