title: Efficiency and internal noise for detection of suprathreshold patterns measured using simple reaction time.
abstract: Studies of the detection of simple visual patterns at threshold contrast have found that human performance is limited by the addition of internal noise and by the sub-optimal sampling efficiency of the visual system. Many common visual tasks require the detection of a signal having a contrast well above threshold, and we sought to measure the internal noise and sampling efficiency for such signals using simple reaction time (RT). Observers were presented with suprathreshold Gabors in dynamic Gaussian white noise and were required to hit a button as soon as each was detected. By comparing the RT variances from humans to those of an ideal observer, visuomotor internal noise and sampling efficiency were measured. The internal noise remains constant and the sampling efficiency increases as the signal contrast increases.
authors.affiliation: SMART--DRDC Toronto, 1133 Sheppard Avenue West, PO Box 2000, Toronto, Ontario, Canada M3M 3B9. william.simpson@drdc-rddc.gc.ca
authors.forename: William A
authors.initials: WA
authors.lastname: Simpson
authors.forename: Kellyanne
authors.initials: K
authors.lastname: Findlay
authors.forename: Velitchko
authors.initials: V
authors.lastname: Manahilov
mesh_terms: D015350:Contrast Sensitivity / Q000502:physiology*; D006801:Humans; D011601:Psychophysics; D011930:Reaction Time; D012684:Sensory Thresholds / Q000502:physiology*