Hemispheric differences in the perception of gratings

Szela̧g, Elżbieta; Budohoska, W; Koltuska, B.

doi:10.3758/bf03330295

Cited by 20 publications

(6 citation statements)

References 27 publications

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“…It is obvious that their results are limited. Szelag, Budohoska, and Koltuska (1987), who used a wide range of base spatial frequencies, found no evidence for hemispheric differences in the time needed to discriminate whether two successively presented gratings were the same or different. However, the changes in mean luminance that accompanied presentation of the gratings might have differentially masked high and low spatial frequencies (Badcock & Sevdalis, 1987).…”

Section: Strategy 2: Simple Stimulimentioning

confidence: 99%

Hemispheric differences are found in the identification, but not the detection, of low versus high spatial frequencies

Kitterle

Christman

Hellige

1990

Perception & Psychophysics

154

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The processing of sine-wave gratings presented to the left and right visual fields was examined in four experiments. Subjects were required either to detect the presence of a grating (Experiments 1 and 2) or to identify the spatial frequency of a grating (Experiments 3 and 4). Orthogonally to this, the stimuli were presented either at threshold levels of contrast (Experiments 1 and 3) or at suprathreshold levels (Experiments 2 and 4). Visual field and spatial frequency interacted when the task required identification of spatial frequency, but not when it required only stimulus detection. Regardless of contrast level (threshold, suprathreshold), high-frequency gratings were identified more readily in the right visual field (left hemisphere), whereas low-frequency gratings showed no visual field difference (Experiment 3) or were identified more readily in the left visual field (right hemisphere) (Experiment 4). Thus, hemispheric asymmetries in the processing of spatial frequencies depend on the task. These results support Sergent's (1982) spatial frequency hypothesis, but only when the computational demands of the task exceed those required for the simple detection of the stimuli.Perceptual characteristics of input, as well as cognitive characteristics of task, have been shown (by, e.g., Sergent & Hellige, 1986) to influence obtained patterns of cerebral asymmetry. Sergent (1982Sergent ( , 1983 proposed that the right visual field/left hemisphere (RVF/LH) is specialized for the perceptual processing of higher spatial frequencies, and that the left visual field/right hemisphere (LVF /RH) is specialized for the processing of lower spatial frequencies. Two general strategies, one involving complex stimuli and the other, simple stimuli, have been employed in testing this hypothesis, and each strategy will be discussed below in turn. Strategy 1: Complex StimuliFirst, some researchers have used complex stimuli (e.g., alphanumeric characters, faces) and have varied input characteristics (e.g., size, eccentricity, luminance, exposure duration) in order to vary the proportion of high and low frequencies in the input. When Christman (1989) reviewed such studies, he found moderate support for the spatial frequency hypothesis. However, the manipulations used in these studies have only crude and/or indirect effects on the spatial frequency content of the input, and thus they cannot be considered simple or straightforward manipulations of spatial frequency as opposed to other input variables (e.g., stimulus perceptibility; see Michimata & Hellige, 1987).In only four studies have quantitative forms of spatial filtering been employed to directly test the spatial frequency hypothesis. Sergent (1985) presented clear versus low-pass blurred faces and found, as predicted by the hypothesis, that low-pass blurring produced greater relative LH impairment. In a similar experiment, however, Sergent (1987) obtained an LH advantage with broad-pass faces and no hemispheric differences with low-pass faces. Christman (1990) used dioptric blur...

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Section: Strategy 2: Simple Stimulimentioning

confidence: 99%

Hemispheric differences are found in the identification, but not the detection, of low versus high spatial frequencies

Kitterle

Christman

Hellige

1990

Perception & Psychophysics

154

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“…In our experiment, we randornly varied the phase of both the base and comparison gratings over trials to prevent subjects from using localluminance cues as a basis for discrimination. This was not the case for Grabowska et al (1989) or Szelag et al (1987). It is possible that subjects could have based their discrimination on whether the localluminance maxima or minima in the two flashes coincided rather than on the spatial frequency per se.…”

Section: Methodsmentioning

confidence: 99%

“…Since eye movements were not monitored, it is quite possible that they may have accounted for the failure to find any evidence for a spatial frequency x visual field interaction even though a more sensitive measure, RT, was used. For example, in Szelag et al (1987), the total time was greater than 1 sec (i.e., 40-msec exposure of each grating pattern and a 1.5-sec interstimulus interval). Although eye movements were not monitored in the present experiment, we attempted to minimize their effect by keeping the total presentation time of the stimulus display relatively short and strongly emphasized to subjects that to perform the discrimination task accurately, it was necessary to maintain fixation.…”

Section: Methodsmentioning

confidence: 99%

Visual field effects in the discrimination of sine-wave gratings

Kitterle

Selig

1991

Perception & Psychophysics

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The time needed to deeide whether the second of two sueeessively presented sinusoidal gratings was of a higher or lower spatial frequeney than the first was measured for spatial frequeneies of 1, 2, 4, 8, and 12 eyeles per degree (cpd) presented in either the left visual field (LVF) or right visual field (RVF). A LVF advantage was found for discriminating within the low-spatialfrequency range (i.e., 1 and 2 cpd), whereas a RVF advantage was found for discriminating within the high-spatial-frequeney range (i.e., 4-12 cpd), These findings support the eonclusion that hemispherie asymmetries in the processing of gratings arise when eomparisons are made between the output of spatial-frequeney ehannels.

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“….50 Whitman, 1981), most investigators report no differences (Beaton & Blakemore, 1981;Blake & Mills, 1979;Delis, Robertson, & Efron, 1986;Fiorentini & Berardi, 1984;Kitterle & Kaye, 1985;Rijsdijk, Kroon, & van der Wildt, 1980;Rose, 1983;Szelag, Budohoska, & Koltuska, 1987;Vassilev, Verskaya, Manahilov, Mitov, & Leushina, 1985). Kitterle (1986) provides a review of this literature.…”

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confidence: 99%