Ecological optics and visual slant.

Freeman, Robert B.

doi:10.1037/h0022614

Cited by 30 publications

(23 citation statements)

References 4 publications

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“…In an interchange of papers, Flock (1965) and Freeman (1965Freeman ( , 1966b have debated the relative merits of optical theta and perspective as explanations of slant perception. Freeman argues that optical theta requires too complex an analytical operation to be a likely perceptual process.…”

Section: Discussionmentioning

confidence: 99%

Perspective and form ratio as determinants of relative slant judgments.

Braunstein¹,

Payne²

1969

Journal of Experimental Psychology

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Judgments of relative slant were elicited by a paired-comparison method from 24 S"s in each of three experiments. The stimuli were computergenerated slides representing regular dot patterns (Exp. I), regular line patterns (Exp. II), or random dot patterns (Exp. Ill) rotated about a horizontal axis.The ratio of horizontal to vertical separations (form ratio) and perspective were independently varied in Exp. I and II. Perspective clearly dominated slant judgments when in conflict with form ratio as an indicator of degree of slant. Perspective alone was varied in Exp. Ill and was found to be less effective in determining slant judgments for random dot patterns. The equivalence of perspective and optical theta as explanations of slant perception is discussed.

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Section: Discussionmentioning

confidence: 99%

Perspective and form ratio as determinants of relative slant judgments.

Braunstein¹,

Payne²

1969

Journal of Experimental Psychology

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“…In his criticism of my theoretical paper on visual slant perception (Flock, 1964a), Freeman (1965) claims that variables of surface texture are both ineffectual and unnecessary for the perception of slant. He argues that all perceived slants are a function primarily of linear outline perspective (contour convergence) and that the greater the linear perspective the greater the judged visual slant.…”

Section: Dartmouth Collegementioning

confidence: 99%

“…At the superficial level that I have described these data, it would seem that there might be some basis for Freeman's (1965) claim. But let us look more closely at these experiments cited by Freeman.…”

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confidence: 99%

Optical texture and linear perspective as stimuli for slant perception.

Flock¹

1965

Psychological Review

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“…Flock considered contour gradients containing linear perspective to be special cases of texture gradients, while Freeman considered texture gradients to be special cases of contour gradients. Braunstein (1976) observes that both Flock (1964aFlock ( , 1965 and Freeman (1965Freeman ( , 1966b were in a sense correct and emphasizes that the same mathematical information for slant is available from each source, although he warns that the perceptual salience of different sources varies situationally. Braunstein's point can be expanded to include all sources of information about surface slant.…”

mentioning

confidence: 99%

“…All of the studies just cited investigated a single SOurce of information or placed two sources in competition to determine which was perceptually more salient or which yielded more accurate judgments. Methodological concerns seemed to require isolation of sources of information, thereby fostering debate concerning the primacy of various sources, such as the exchange between Flock (1964aFlock ( , 1965 and Freeman (1965Freeman ( , 1966b. Flock considered contour gradients containing linear perspective to be special cases of texture gradients, while Freeman considered texture gradients to be special cases of contour gradients.…”

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confidence: 99%

The rotating square illusion

Mingolla

Todd

1981

Perception & Psychophysics

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Twenty subjects viewed displays of square and trapezoidal luminous dot figures rotating about a vertical axis in both polar and parallel projections. The frequency of reported oscillation of the rotating figures was as high for the squares as for the trapezoids. provided that the squares contained static slant information in the form of internal texture gradients. Previously reported oscillation effects using shapes other than trapezoids have generally been unreliable. with a subject as likely to see rotation as oscillation for a given cycle. and then only in parallel projection. As a consequence, linear perspective information in trapezoidal shape has been taken to be the indispensable element for obtaining a strong oscillation effect. The authors argue that in the construction of the rotating object. a required condition for reliably producing the effect is a violation of some optical constraint regarding slant information, not necessarily one involving linear perspective.

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Ecological optics and visual slant.

Cited by 30 publications

References 4 publications

Perspective and form ratio as determinants of relative slant judgments.

Perspective and form ratio as determinants of relative slant judgments.

Optical texture and linear perspective as stimuli for slant perception.

The rotating square illusion

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