The Perception and Identification of Mirror-Reversed Patterns

Bradshaw, John L.; Bradley, Dianne; Patterson, Kay

doi:10.1080/14640747608400553

Cited by 38 publications

(20 citation statements)

References 87 publications

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“…For example, rotations through angles close to 90' can greatly reduce recognisability, although this effect is much less for rotations through 180' and for reflections (Dearborn, 1899;Rock, 1973;Foster, 1978 (Attneave, 1950), discrimination of mirror images (Sekuler and Rosenblith, 1964;Sekuler and Pierce, 1973), and identification of parafoveal figure pairs (Banks, Bachrach and Larson, 1977;Banks, Larson and Prinzmetal, 1979;Chastain and Lawson, 1979), have all been shown to depend on the relative positions of the stimuli. Also the time taken to report sameness of mirror pairs has been found to be shorter when the patterns are presented symmetrically about the point of fixation than when they are both presented to one side (Corballis and Roldan, 1974;Bradshaw, Bradley and Patterson, 1976). Similarly, it has been demonstrated that symmetry in a complex random-dot pattern is best perceived when the observer fixates a point on the axis of symmetry (Julesz, 1971; Barlow and Reeves, 1979; see also Bruce and Morgan, 1975).…”

Section: Introductionmentioning

confidence: 91%

Visual Comparison of Rotated and Reflected Random-Dot Patterns as a Function of Their Positional Symmetry and Separation in the Field

Kahn

Foster

1981

The Quarterly Journal of Experimental Psychology Section A

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Subjects viewed pairs of random-dot patterns which were presented in a number of arrangements varying in the transformations applied to the patterns, in the distance between the patterns, and in the symmetry of the pattern positions with respect to the point of fixation. The task was to judge whether the patterns were “the same” taking into account possible rotations or reflections, or “different”. It was found that correct judgements for identical patterns were most affected by the distance between the two patterns, whereas correct judgements for patterns where one had been rotated through 180° or reflected were most affected by the symmetry of the pattern positions. A scheme modelling the visual recognition of transformed patterns, sufficient to explain the results, is presented.

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Section: Introductionmentioning

confidence: 91%

Visual Comparison of Rotated and Reflected Random-Dot Patterns as a Function of Their Positional Symmetry and Separation in the Field

Kahn

Foster

1981

The Quarterly Journal of Experimental Psychology Section A

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“…This is a remarkable resolution and very close to the two-point threshold for fields comprising identical point-pairs (approximately 2 min of arc). Therefore, this process is probably the same as that which Mach (1886) considered so important to the problem of form vision, and which has been investigated subsequently using a wide variety of stimuli, such as geometric shapes and letters (e.g., Bradshaw, Bradley, & Patterson, 1976;Corballis, Miller, & Morgan, 1971;Sekuler & Pierce, 1973;Staller & Sekuler, 1977).…”

Section: Colllnearity Of Midpointsmentioning

confidence: 98%

Component processes in the perception of bilaterally symmetric dot textures

Jenkins

1983

Perception & Psychophysics

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If a random-dot texture is reflected about a given axis, the resulting bilateral symmetry is immediately detected. In order to account for this ability, it has been suggested that the visual system detects reflection in these dot textures because of the existence of a symmetric neural organization, centered about the fovea, which performs a point-by-point analysis. As yet, there is no evidence of such an organization in the human visual system. An alternative description of a bilaterally symmetric texture, that of a two-dimensional distribution of uniformly oriented point-pair elements, of nonuniform size and with collinear midpoints, is more consistent with known mammalian visual-system neurophysiology. Experiments were conducted in order to determine whether the human visual system is sensitive to the orientational uniformity of otherwise nonuniform point-pair elements and to their midpoint collinearity. The results indicate that there are three processes involved in the perception of bilaterally symmetric dot textures: the detection of orientational uniformity of the different sized point-pair elements; the fusion of salient element point-pairs into a salient feature; the detection of the symmetry of the resulting feature. This component-process hypothesis eliminates the necessity to postulate the existence of a symmetrical neural organization centered about the fovea.433

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“…It is also possible that the information concerning relative orientational sensitivity is biased in many previous studies (see Bradshaw, Bradley, & Patterson, 1976, for a complete discussion of problems in this regard). In the experiments reported here, the sensitivity of each orientation was measured independently of every other orientation, with each being compared to a null stimulus, an equally dense uncorrelated dynamic dot texture.…”

mentioning

confidence: 99%

Orientational anisotropy in the human visual system

Jenkins

1985

Perception & Psychophysics

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A global pattern/randomness threshold was used to investigate orientational anisotropy in the human visual system. Dynamic transpositionally symmetric textures were used, since they allowed the investigation of three theoretically derived variables, size, orientational uniformity, and numerosity, independently and in interaction. The detectability of correlation, as indexed by these thresholds, was found to be dependent on the size of the uniform point-pair elements, d, and their orientation; larger tolerable~d values were found in the vertical meridian. Increasing the stimulus field size increased the absolute value of this threshold, but not the relative value as a function of orientation. The thresholds were also found to be dependent on the orientational uniformity of the point-pairs. Tolerable perturbation did not vary as a function of the uniform orientation until a critical point-pair size was exceeded. This critical point-pair size did vary as a function of orientation, falling quite distinctly from vertical, to horizontal, to oblique. The number of point-pair elements comprising the textures did not affect the global pattern/randomness threshold. The implications of these data for the neural mechanisms underlying the "oblique effect" were examined, and it was concluded that an orientational anisotropy might exist in the length of receptive fields serving functional units selectively sensitive to orientation. It was also concluded, however, that this factor alone could not account for the various examples of the orientational anisotropy in vision, and that any anisotropy measured in human vision might be the net product of more than one anisotropy existing within and between the various levels of processing in the human visual system.

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The Perception and Identification of Mirror-Reversed Patterns

Cited by 38 publications

References 87 publications

Visual Comparison of Rotated and Reflected Random-Dot Patterns as a Function of Their Positional Symmetry and Separation in the Field

Visual Comparison of Rotated and Reflected Random-Dot Patterns as a Function of Their Positional Symmetry and Separation in the Field

Component processes in the perception of bilaterally symmetric dot textures

Orientational anisotropy in the human visual system

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