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Masayoshi Nagai, Patrick J. Bennett, Allison B. Sekuler; Spatiotemporal templates for detecting 1st- and 2nd-order orientation- and luminance-defined targets. Journal of Vision 2005;5(8):481. doi: 10.1167/5.8.481.
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© ARVO (1962-2015); The Authors (2016-present)
Using the classification image technique, the present experiments revealed several characteristics of human observers' spatiotemporal templates for the detection of texture-defined targets. The stimulus consisted of a five frame (each frame: 80 ms) movie of a five by five spatial array of elements (whole size: 1.6 x 1.6 deg). The target was defined by the first-and the second-order characteristics of orientation- and luminance-defined textures and observers were required to respond whether a target or non-target was presented on each trial. When a target signal was presented across all five frames, human observers typically relied on the most reasonable cues in all five frames for detecting targets. In other words, they used the first-order cue for detecting the first-order target and used the second-order cue for detecting the second-order target. When the target signal was presented just during the third temporal frame, the temporal profile of the observers' spatiotemporal templates changed, so that only information presented near the third temporal frame was used. In addition, the type of spatial cue utilized also changed, so that for first-order target detection observers used second-order cues as well as first-order cues. This strategy was sensible, because both first- and second-order cues were available in this condition. There also was a trend toward increasing the extent of spatial information used when the temporal information was restricted, perhaps indicating that there is a space-time tradeoff in the information that can be used in these tasks.
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