Further developments in the assimilation theory of geometric illusions: The adjacency ,principle

Pressey, Alexander W.; Murray, Robert P.

doi:10.3758/bf03211223

Cited by 64 publications

(75 citation statements)

References 19 publications

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“…These results argue against framing ratio as the predictor of illusion magnitude. It seems that the predictor of assimilation magnitude in this case was the amount of the contextualline falling within the attentive field; the greater the contextual line's extent within the attentive field, the greater the assimilation magnitude (the "range" postulate, Pressey & Murray, 1976). Contextual line extents outside of the attentive field are ineffective in producing assimilation and may produce contrast (Pressey & Wilson, 1980).…”

Section: Resultsmentioning

confidence: 99%

Orientation specificity of length assimilation and contrast

Jordan

Haleblian

1988

Perception & Psychophysics

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The orientation specificity of length assimilation and contrast was assessed using the parallellines array. The purpose was to determine the nature of the representation oflength both within and outside of the "attentive field." Experiments 1 and 2 demonstrated that when both contextual and test lines are within an attentive field and do not intersect, the resulting simultaneous length assimilation is independent of orientation. In Experiment 3, simultaneous length contrast was produced by placing the contextual line outside of the attentive field; it also was independent of orientation. Finally, Experiment 4 demonstrated that the sequential length contrast (length aftereffect) produced by a 5-sec prior inspection of a contextual line was independent of orientation, whereas the contrast produced by 60 sec of contextual-line inspection showed some degree of orientation specificity. These results, combined with those obtained with orientation illusions (Tyler & Nakayama, 1984;Wenderoth & Johnson, 1984;Wenderoth, O'Connor, & Johnson, 1986), suggest a qualitative relationship of length and orientation coding that is characterized by partial and mutual overlap of length and orientation information.The parallel-lines array is a minimal configuration for producing an illusion of perceived length. The direction of this distortion of perceived length depends on the spatial and temporal relationship of the test line and a parallel contextual line. In the usual parallel-lines array, the contextual and test lines are presented simultaneously and spatially proximal, and length assimilation is observed. For example, at a viewing distance of 40 em, a 9-cm horizontal contextual line will produce overestimation of a parallel 6-cm test line located 5 mm below it. However, length contrast has been demonstrated in the array under conditions of simultaneous viewing with a much larger spatial separation (100 mm) of the same contextual and test lines (Jordan & Schiano, 1986) and under conditions of sequential presentation of contextual and test lines within the aftereffect paradigm (Brigell & Uhlarik, 1979;Jordan & Uhlarik, 1985). Jordan and Schiano (1986) proposed revisions of descriptive models of length distortion that account for the reversals from length assimilation to length contrast outlined above. Their model is essentially a hybrid of Girgus and Coren's (1982) "pool and store" model of perceptual distortion and the most recent revision of Pressey's assimilation theory (Pressey & Wilson, 1980). According to Girgus and Coren's model, the visual information-processing system imposes constraints on the amount or the area of an array that an observer can sample simultaneously. The lengths of spatially proximal ele-. ments in an array are perceptually "pooled," resulting Preparation of this report was supported by NASA Grant NCC-2-327 to San Jose State University, Kevin Jordan, Project Director. Jerayr Haleblian is now at the University of Southern California. The authors are pleased to acknowledge the helpful comments of two anon...

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Section: Resultsmentioning

confidence: 99%

Orientation specificity of length assimilation and contrast

Jordan

Haleblian

1988

Perception & Psychophysics

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“…For very large distances the estimates increased again, approaching the control line for the longer distances (see Figure 2; i.e., the illusion diminished). According to Length illusions and attentional deployment 225 Pressey and Murray (1976), contour marks widely separated from the stimulus length would fall outside the attentive field and therefore have less influence on its perceived length. We found assimilation as well as contrast (cf.…”

Section: Control Conditionsmentioning

confidence: 99%

“…Pressey (1974) proposed a hypothetical attentional field surrounding the focal stimulus in which an assimilation process is effective. Pressey and Murray (1976) proposed a quantitative version of this spatial model. Because the notion of an assimilation process does a good job in predicting several variants of the Müller-Lyer displays (Pressey & Kersten, 1989), we are mainly interested in the idea of a spatial attentive field.…”

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confidence: 99%

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Length illusions and attentional deployment

Kersten

2000

Jpn Psychol Res

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Length illusions are caused by the systematic manipulation of size ratios. The principle of relational determination (i.e., framing ratio) holds for different classical illusional displays and is described as a failure of selective attention that facilitates size constancy. Implementing a spatial distance (D) between the focal stimulus (of length F) and the contour marks (of length B) leads to illusions that contradict the description in terms of a simple framing ratio. The stimulus configuration rather than the framing ratio determines the illusions (two different ratios are independently effective, D/F and B/F). The relational determination of length illusions contradicts explanations in terms of either efferent readiness or attentional deployment. In a developmental approach, it was shown that a failure of selective attention to the length of the focal stimulus due to relational determination holds only for adults (aged 21–32 years). The B/F ratio tended to effectiveness in determining the illusions for children aged 7–9 years, but not for children aged 5–6 years. The absolute size of D, regardless of F, determined the illusional trends of both groups of children. The failure of selective attention, which facilitates size constancy, in judging length illusions seems to develop first for contour size and later for spatial distance.

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“…Variations on these defmitions appeared in Pressey and Murray (1976), Pressey, Di1.ollo, and Tait (1977), Pressey and Di1.ollo (1978), and Pressey and Wilson (1980). The most recent definition was given by Pressey and Kersten (1989):…”

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confidence: 99%