Perceptual Latency Research Articles

Perceptual latencies are shorter for motion towards the fovea than for motion away

Subjects had to align a brief test flash with a peripheral steady reference target during ocular pursuit, or with a moving reference target during steady eye fixation. The performance was determined by the direction of movement, of the reference target image on the retina—towards or away from fovea. The data are explained by the hypothesis that the passage of a retinal locus by a moving target image is experienced faster when the image moves foveopetally, regardless of whether the passage is caused by real target movement or by ocular pursuit.

Threshold models of temporal-order judgments evaluated by a ternary response task.

This article examines various predictions of temporal-order judgment models (triggered-moment, attention-switching, and perceptual-moment models). These model tests are based on a ternary response-category approach: In each trial two stimuli (e.g., a tone and a light) are presented at times tx and ty, respectively. The time difference d = ty-tx was varied for each trial. After each presentation the subject selected one of three possible responses (“tone and light simultaneously,” “tone first,” or “light first”). Two psychometric functions can be generated from these response categories. It is shown that several models of temporal-order judgments constrain the relationship between these two functions. It was examined for different data sets whether the predicted relationships are satisfied. Several violations of the predicted relationships were observed, providing strong evidence against perceptual-moment models, triggered-moment models, and certain versions of attention-switching models. The proposed tests for each model do not depend on specific distributional assumptions of perceptual latencies. A modified attention-switching model with dwell times depending on stimulus properties might account for the present findings.

Perceptual latency and spatial frequency

Subjects estimated the perceived onset of sinusoidal gratings by adjusting a visual probe so that grating and probe were phenomenally simultaneous. The first experiment found that perceptual latency increased by an average of 21 msec over a range of 0.5–9.0 c/deg, or approximately 5 msec per octave of spatial frequency. A second experiment found, that when a fundamental frequency and its third harmonic at one third contrast are compared, a lag of between 21 and 25 msec for the higher frequency lower amplitude grating is obtained. These spatial frequency dependent delays are substantially lower than those reported using other methods.

Reaction times to different spatial frequencies as a function of detectability

Simple reaction time to sine-wave gratings of 1, 4 and 10 c/deg was measured as a function of the detectability of the gratings. Reaction time increased with spatial frequency over a range of detectabilities. Assuming that equally detectable gratings produce equivalent levels of response in the visual system, this increase in reaction time reflects an increase in perceptual latency as spatial frequency is increased.

Appearance of short‐exposure colorlight–two successive colors and single color

AbstractWhen comparing the three primary colors red, green and blue of equal luminance, the perceptual latency of blue is proved to be longer than that of red and green. Also, when two of the three primary colors are presented successively, the resultant color appears close to the second. This latter phenomenon suggests the presence of a temporal masking effect in the color mechanism. From these two phenomena, the fact that light from dark conditions of cyan and magenta presented for a short, rather than long, time appears close to blue because the perceptual latency of blue is longer compared to the other two. This is reasonably attributable to the color masking effect.

等明るさ色相変化の知覚潜時と輝度差の影響

等明るさ色相変化の知覚潜時と輝度差の影響

Muscular tone at rest: relationship with cutaneous pleasurable experience, an interpretation according to the dimensional approach to cerebral dominance.

This study examined some aspects of the relationship between muscular tone at rest and a particular kind of pleasurable tactile stimulation (tickle) in the light of the dimensional approach to cerebral dominance. Electromyographic scores, latencies, and tickle durations for six muscles and corresponding skin areas were taken both on the right and left sides of the body from 40 female students in psychology. There was an inverse relationship between muscular tone at rest and sensitivity to tickle stimulation, which is lower (long latency and brief duration of perception) when the levels of muscular tone increase. So we hypothesize that the muscular system (especially because the correlations of tone and latency are positive) plays a role through the afferents of inhibition of tactile pleasurable experience. This role is more evident for the left side of the body. The dimensional approach to cerebral dominance on the basis of myographic score identified three groups of subjects (right, left, and non-dominant). The subjects classified as right-dominant on the basis of myographic score show a longer duration of tickle on the right half of the body than on the left and longer latency on the left. The left-dominant subjects do not show any difference between the two halves of the body in duration of tickle but show longer latency on the left side. The non-dominant subjects show also no difference between the two sides of the body for both tickle duration and latency.

Multiple sclerosis. Luminance threshold and measurements of temporal characteristics of vision.

Luminance threshold, perceptual latency, double-flash resolution, and critical flicker frequency were examined in patients with multiple sclerosis (MS) and in normal control subjects. The intensities of the stimuli used to test the temporal properties of vision were equalized with respect to individual luminance thresholds. In eight patients with MS, all the properties tested showed abnormality, double-flash resolution being most commonly affected. Retinal sites were not however, uniformly abnormal according to these measures. We conclude that abnormal temporal properties of vision in patients with MS are not a simple functional consequence of altered luminance thresholds.

The physiological basis of variations in visual latency

By comparing physiological and psychophysical measures of visual latency one can use suprathreshold stimuli to explore the relationship between perception and its underlying physiology. Experiments to do this show that only if the physiological measure takes account of the noisy maintained discharge of cells can one satisfactorily explain the effects of flash strength, flash duration and background illumination upon perceptual latency.

Effects of stimulus duration on perceptual latency in the fovea

Perceptual latency to a foveal stimulus was determined with the perceived-order method. In Experiment 1, luminance ranged from 29 to 114,000 td, stimulus durations ranged from 2 to 2,500 msec, and all stimuli were 100% detectable. One observer showed no significant duration effect, and the other showed a significant, but irregular, effect. In Experiment 2, absolute threshold was determined at the same durations, and perceptual latencies were subsequently determined with luminance.1 log above absolute threshold (100% detectable). Latencies increased at long durations for both observers. This result can probably best be explained in terms of probability summation.

Dark adaptation and the Hermann grid illusion

The latency of the perception of the dark spot at the intersection of a Hermann grid was measured before and after dark adaptation. It was found that dark adaptation significantly increased the latency of perception of the spot while light adaptation had no effect. This finding was predicted from the Jung and Spillman account of the Hermann grid illusion and from the Kuffler et al. finding that inhibitory receptive fields of the cat’s retinal ganglion ceils are reduced in size and responsiveness after dark adaptation. The significance of this finding in relation to other simultaneous contrast phenomena is discussed.

Perceptual latencies to sinusoidal gratings

Simple visual reaction time (RT) to suprathreshold sinusoidal gratings was determined as a measure of perceptual latency. As parameters, spatial frequency, exposure duration and modulation were varied. With three subjects, RT was found to increase with increasing spatial frequency. High contrast gives shorter RTs than low contrast. In the range investigated the effect of contrast is small compared with that of spatial frequency. At constant spatial frequency exposure durations of 30–60 msec produce shortest RTs. Underlying physiological mechanisms are considered. Some evidence comes from different temporal behaviour of X- and Y-system but central mechanisms are also supposed to be involved.

Latency differences to monochromatic stimuli measured by disjunctive reaction time.

Two studies were done in order to assess the effects of wavelength on visual perceptual latency as measured in a disjunctive RT paradigm. The results of the first study, though not statistically significant, suggested a trend toward shorter RT to longer wavelength stimuli. In the second study, using well-practiced subjects, significant differences were found between disjunctive RT to red and green stimuli. The results suggest that latency differences as a function of wavelength are demonstrable in an experimental situation in which the subject must react to chromatic information, as differentiated from brightness information.

The “fluttering heart” and spatio-temporal characteristics of color processing—I: Reversibility and the influence of luminance

The classic phenomenon of the “fluttering heart” was investigated in two experiments. It was demonstrated that the effect consists of a genuine delay and not a phase difference. Its reversibility presents serious problems for two earlier explanations based on the dependence of perceptual latencies on wave-length and the differential latencies of the rod and cone apparatus, respectively. It was further shown that a luminance difference between target and background is neither a sufficient nor a necessary condition, but that a color difference is necessary. It was suggested that interactions between the color processing mechanisms across the chromatic border are involved.

The relationship between judgments of successiveness

The purpose of the present set of experiments was to determine the nature of the relationship between judgments of successiveness and judgments of order. The relationship was examined in terms of models which assume that the perception of successiveness is sufficient for the perception of correct temporal order. It was demonstrated that successiveness and order judgments cannot be jointly explained by perceptual latency models which assume that both judgments are based on the same internal event. This is the case regardless of the form of the perceptual latency distribution, and for either a threshold or a nonthreshold decision process. On the other hand, performance on a successiveness discrimination task, an order discrimination task, and a task requiring both a successiveness and an order judgment on each trial is consistent with the predictions of the attention-switching model.

Effects of stimulus duration on temporal facilitation

High-luminance surrounds can reduce perceptual latency (temporal facilitation). Test stimuli of four durations (5 msec, 100 msec, 5-sec onset, and 5-sec offset) were judged against comparison stimuli of several durations. Temporal facilitation of almost 100 msec was obtained with the 5-msec test regardless of the comparison used. With 100 msec and 5-sec onset test stimuli, temporal facilitation was less and occured only with identical test and comparison stimuli. Offset latencies were shorter than onset latencies, and only one S showed temporal facilitation with offset test stimuli. Results were discussed in terms of the temporal course of brightness.

Perceptual latency as a function of stimulus onset and offset and retinal location

Relative perceptual latency to stimulus onset and to stimulus offset was determined in the fovea and parafovea using the perceived-order method. Offset latency was shorter than onset latency at all luminance levels in the fovea. In the parafovea, however, offset latency was found to be shorter than onset latency only at low test stimulus luminances; offset and onset functions converged at higher luminance levels. Contradictory findings obtained in early phases of the present study and conflicting results existing throughout onset-offset literature are discussed in terms of visual persistence.

Effects of surround luminance on perceptual latency in the fovea.

The effect of surround luminance on relative latency of response to a test stimulus was measured with the perceived-order method in which asynchrony between two lights is varied to make the lights appear subjectively simultaneous. Increasing surround luminance from zero to levels high enough to impair test-stimulus detectability resulted in reduction of test-stimulus latency (facilitation of response speed) by 100 ms both in the rod-free area of the fovea and in the periphery. Since appreciable facilitation of response speed was obtained in the rod-free area of the fovea, suppression of visual noise would seem to be a more plausible explanation of the facilitation effect than inhibition of rod activity. Variation of surround luminance was also found to have a much greater effect than variation of test-stimulus luminance.

Effects of surround luminance on perceptual latency.

The apparent brightness of a test field can be substantially reduced by an extended-duration surround. In experiment I, test-field luminance was adjusted to match the brightness of a reference stimulus. Over a wide range of surround luminance, latency was measured by comparing test-stimulus and surround-field onsets, using the perceived-order method, in which the temporal interval between the two stimuli is varied to obtain subjective simultaneity. A series of control observations was made using test stimuli covering the same range of test-stimulus luminance that was used in the main series of observations, but with no surround field. Latencies of test stimuli were found to be considerably shorter with high-luminance surround fields than with no surround. Apparently, high-luminance surrounds resulted in reduction of latency of response to the test stimulus (facilitation of response to the test stimulus). In experiment II, a constant test-stimulus luminance was used. Reduction of latency of response to the test stimulus was found to increase with increasing surround luminance when surround luminance exceeded test-stimulus luminance. Supplementary observations indicated that the reduction of test-stimulus latency was not an artifact of dark adaptation.

Studies of visual backward masking and a model for the Crawford effect

Three experiments are described which involve the masking of a visual test stimulus by a subsequent stimulus, employing overlapping flash stimuli (the Crawford effect). The effect does not depend on the hue of the masking stimulus; it may be produced by the offset rather than the onset of the masking stimulus; it is increased by decreasing the size of the test stimulus; and, the backward masking effect closely resembles the phenomenon of apparent simultaneity. In all cases, a wide range of inter-stimulus intervals (e.g., 40 msec) covered the transition between masking and no masking. The obtained masking and simultaneity functions, based on forced-response detection procedures, were interpreted in terms of a two-factor model, involving perceptual latency differences and the quantization of psychological time; the predictions of this model in general were supported.