On the search for an appropriate metric for reaction time to suprathreshold increments and decrements

Vassilev, A.; Murzac, Adrian; Zlatkova, Margarita; Anderson, R. H.

doi:10.1016/j.visres.2008.12.010

Cited by 9 publications

(32 citation statements)

References 19 publications

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“…We quantified the luminance contrast as a % Weber fraction-Weber luminance contrast-in relation to isoluminant condition because it seems to be appropriate for a contrast metric for cone RT Vassilev et al, 2009). We quantified the luminance contrast as a % Weber fraction-Weber luminance contrast-in relation to isoluminant condition because it seems to be appropriate for a contrast metric for cone RT Vassilev et al, 2009).…”

Section: Resultsmentioning

confidence: 99%

The effect of chromatic and luminance information on reaction times

2010

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We present a series of experiments exploring the effect of chromaticity on reaction time (RT) for a variety of stimulus conditions, including chromatic and luminance contrast, luminance, and size. The chromaticity of these stimuli was varied along a series of vectors in color space that included the two chromatic-opponent-cone axes, a red-green (L-M) axis and a blue-yellow [S - (L + M)] axis, and intermediate noncardinal orientations, as well as the luminance axis (L + M). For Weber luminance contrasts above 10-20%, RTs tend to the same asymptote, irrespective of chromatic direction. At lower luminance contrast, the addition of chromatic information shortens the RT. RTs are strongly influenced by stimulus size when the chromatic stimulus is modulated along the [S - (L + M)] pathway and by stimulus size and adaptation luminance for the (L-M) pathway. RTs are independent of stimulus size for stimuli larger than 0.5 deg. Data are modeled with a modified version of Pieron's formula with an exponent close to 2, in which the stimulus intensity term is replaced by a factor that considers the relative effects of chromatic and achromatic information, as indexed by the RMS (square-root of the cone contrast) value at isoluminance and the Weber luminance contrast, respectively. The parameters of the model reveal how RT is linked to stimulus size, chromatic channels, and adaptation luminance and how they can be interpreted in terms of two chromatic mechanisms. This equation predicts that, for isoluminance, RTs for a stimulus lying on the S-cone pathway are higher than those for a stimulus lying on the L-M-cone pathway, for a given RMS cone contrast. The equation also predicts an asymptotic trend to the RT for an achromatic stimulus when the luminance contrast is sufficiently large.

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Section: Resultsmentioning

confidence: 99%

The effect of chromatic and luminance information on reaction times

2010

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“…This gives an average estimate of 38 ms for within hemifield shifts and 55 ms for across hemifields shifts. One could argue that the difference of luminance of the cues could affect the reaction times [17]. However, this difference seems not to be sufficient to generate significant differences in subject's reaction times according to the chromatic contrast between the two cues [18].…”

Section: Discussionmentioning

confidence: 99%

“…The shift cue had a luminance of 16.7 cd/m 2 while the stay cue had a luminance of 9.3 cd/m 2 . Both luminance [17] and chromatic contrast [18] have been shown to affect reaction times. These studies predict in particular reaction times trends between Stay and Shift trials opposite to those described here, suggesting that the observations provided therein do not apply to our experimental context.…”

Section: Methodsmentioning

confidence: 99%

The Spatial and Temporal Deployment of Voluntary Attention across the Visual Field

2009

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Several studies have addressed the question of the time it takes for attention to shift from one position in space to another. Here we present a behavioural paradigm which offers a direct access to an estimate of voluntary shift time by comparing, in the same task, a situation in which subjects are required to re-engage their attention at the same spatial location with a situation in which they need to shift their attention to another location, all other sensory, cognitive and motor parameters being equal. We show that spatial attention takes on average 55 ms to voluntarily shift from one hemifield to the other and 38 ms to shift within the same hemifield. In addition, we show that across and within hemifields attentional processes are different. In particular, attentional spotlight division appears to be more difficult to operate within than across hemifields.

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“…We do not make direct comparisons between the RTs for stimuli mediated via different pathways because they are measured using different stimulus contrast ranges, there are differential sensitivities to the photoreceptor excitation types, and the irreducible minimums were not determined due to the available instrument contrast gamut. These issues have been considered elsewhere [21–24,53,54]. …”

Section: Methodsmentioning

confidence: 99%

Effect of rod–cone interactions on mesopic visual performance mediated by chromatic and luminance pathways

et al. 2013

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We studied the effect of rod–cone interactions on mesopic visual reaction time (RT). Rod and cone photoreceptor excitations were independently controlled using a four-primary photostimulator. It was observed that (1) lateral rod–cone interactions increase the cone-mediated RTs; (2) the rod–cone interactions are strongest when rod sensitivity is maximal in a dark surround, but weaker with increased rod activity in a light surround; and (3) the presence of a dark surround nonselectively increased the mean and variability of chromatic (+L−M, S-cone) and luminance (L + M + S) RTs independent of the level of rod activity. The results demonstrate that lateral rod–cone interactions must be considered when deriving mesopic luminous efficiency using RT.

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On the search for an appropriate metric for reaction time to suprathreshold increments and decrements

Cited by 9 publications

References 19 publications

The effect of chromatic and luminance information on reaction times

The effect of chromatic and luminance information on reaction times

The Spatial and Temporal Deployment of Voluntary Attention across the Visual Field

Effect of rod–cone interactions on mesopic visual performance mediated by chromatic and luminance pathways

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