Detection of a luminance increment: effect of temporal uncertainty

Lasley, David J.; Cohn, Theodore E.

doi:10.1364/josa.71.000845

Cited by 49 publications

(40 citation statements)

References 13 publications

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“…However, most previous behavioral experiments have also not manipulated temporal expectation independently of spatial expectation. Effects of temporal expectation on perceptual variables are often reported for foveal or spatially attended items (Lasley & Cohn, 1981;Jepma, Wagenmakers, & Nieuwenhuis, 2012;Marchant, Ruff, & Driver, 2012;Naccache, Blandin, & Dehaene, 2002;Westheimer & Ley, 1996).…”

Section: Discussionmentioning

confidence: 99%

Combining spatial and temporal expectations to improve visual perception

et al. 2014

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The importance of temporal expectations in modulating perceptual functions is increasingly recognized. However, the means through which temporal expectations can bias perceptual information processing remains ill understood. Recent theories propose that modulatory effects of temporal expectations rely on the co-existence of other biases based on receptive-field properties, such as spatial location. We tested whether perceptual benefits of temporal expectations in a perceptually demanding psychophysical task depended on the presence of spatial expectations. Foveally presented symbolic arrow cues indicated simultaneously where (location) and when (time) target events were more likely to occur. The direction of the arrow indicated target location (80% validity), while its color (pink or blue) indicated the interval (80% validity) for target appearance. Our results confirmed a strong synergistic interaction between temporal and spatial expectations in enhancing visual discrimination. Temporal expectation significantly boosted the effectiveness of spatial expectation in sharpening perception. However, benefits for temporal expectation disappeared when targets occurred at unattended locations. Our findings suggest that anticipated receptive-field properties of targets provide a natural template upon which temporal expectations can operate in order to help prioritize goal-relevant events from early perceptual stages.

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Section: Discussionmentioning

confidence: 99%

Combining spatial and temporal expectations to improve visual perception

et al. 2014

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“…Uncertainty in the brightness domain has been studied by Lasley & Cohn (1981), who found a threshold increase of about 0 3 log units when the observer had to judge whether one of eight stimuli had its luminance increased incrementally, compared to the threshold for only one stimulus. This conforms well with our findings in the domain of stereo thresholds (Lindblom & Westheimer, 1992) as well as with the line orientation thresholds in the present study.…”

Section: Discussionmentioning

confidence: 99%

Uncertainty effects in orientation discrimination of foveally seen lines in human observers.

Lindblom

Westheimer

1992

The Journal of Physiology

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SUMMARY1. The effect of spatial uncertainty on line orientation thresholds was studied in normal observers. Vertical lines, 5 min of arc long, built up a matrix in which one of the line elements could be tilted to the left or right. The orientation thresholds depended strongly on the number of alternative test positions. There was a linear relation between log (threshold) and log (P), where P is the probability that a particular line element was the one being tested.2. The uncertainty effect was shown to be time dependent. The effect was more marked for the shortest stimulus duration (1 s). However, even with a 6 s stimulus duration, allowing several re-fixations, the thresholds were significantly higher in the presence of uncertainty, compared to the situation in which the test position was fixed and known to the observer.3. When the measurements were restricted to the centre line in a matrix, thresholds were more than twice as high when the test line could be in any of the centre 3 x 3 positions, compared to the case in which there was no uncertainty as to the test position. Foreknowledge of location of the test line within the matrix improved the threshold further, even if the whole matrix was displaced to different retinal positions.4. It is concluded that the physiological mechanism mediating threshold improvement probably operates on a cortical processing apparatus more central than VI.

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“…This has been shown in a variety of visual tasks such as direction and speed discrimination (Verghese and Stone, 1995;Dobkins and Bosworth, 2001), orientation discrimination (Pavel et al, 1992;Palmer et al, 1993;Palmer, 1994;Baldassi and Verghese, 2002, but see Morgan et al, 1998;Verghese and Nakayama, 1994), luminance discrimination (Cohn and Lasley, 1974;Lasley and Cohn, 1981;Shaw, 1984;Palmer, 1994), color discrimination (Palmer, 1994;Verghese and Nakayama, 1994;Monnier and Nagy, 2001), size and length discrimination (Palmer, 1994), letter discrimination (Bennett and Jaye, 1995;McLean et al, 1997; but see Shaw et al, 1983 andShaw, 1984 for different results when the task is letter localization), as well as contrast detection (Davis et al, 1983 andsee Carrasco et al, 2000). In sum, the consensus across studies is that multiple stimuli can be processed in parallel without any loss in the quality of stimulus processing at an early sensory level.…”

Section: Attentional Weighting Bias: Early Sensory or Decision-based?mentioning

confidence: 92%

Attentional weighting: A possible account of visual field asymmetries in visual search?

Rezec

Dobkins

2004

Spatial Vis

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Several previous visual search studies measuring reaction times have demonstrated scanning biases across the visual field (i.e. a tendency to begin a serial search in a particular region of space). In the present study, we measured visual discrimination thresholds for a target presented amongst distractors using displays that were short enough to greatly reduce the potential for serial (i.e. scanning) search. For both a motion and orientation task, subjects' performance was significantly better when the target appeared in the inferior, as compared to the superior, visual field (no differences were observed between left and right visual fields). These findings suggest that subjects may divide attention unevenly across the visual field when searching for a target amongst distractors, a phenomenon we refer to as 'attentional weighting'. To rule out the possibility that these visual field asymmetries were sensory in nature, thresholds were also measured for conditions in which subjects' attention was directed to the location of the target stimulus, either because it was presented alone in the display or because a spatial cue directed subjects' attention to the location of that target presented amongst distractors. Under these conditions, visual field asymmetries were smaller (or non-existent), suggesting that sensory factors (such as crowding) are unlikely to account for our results. In addition, analyses of set-size effects (obtained by comparing thresholds for a single target vs. the target presented amongst distractors) could be accounted for by an unlimited capacity model, suggesting that multiple stimuli can be processed simultaneously without any limitations at an early stage of sensory processing. Taken together, these findings suggest the possible existence of biases in attentional weighting at a late stage of processing. The bias appears to favor the inferior visual field, which may arise from the fact that there is more ecologically-relevant information in this region of space.

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Detection of a luminance increment: effect of temporal uncertainty

Cited by 49 publications

References 13 publications

Combining spatial and temporal expectations to improve visual perception

Combining spatial and temporal expectations to improve visual perception

Uncertainty effects in orientation discrimination of foveally seen lines in human observers.

Attentional weighting: A possible account of visual field asymmetries in visual search?

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