Induced changes in the perceived orientation of line segments

Bouma, H Herman; Andriessen, JJ

doi:10.1016/0042-6989(70)90104-5

Cited by 96 publications

(52 citation statements)

References 35 publications

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“…Because testing naïve subjects in this same way would have been impractical, a more limited test taking about 3 h was given to rule out the possibility that knowledge of the issues involved might bias performance. The same series of angles was presented, but with the test arm of the inducing angle always oriented at 45°, a choice based on the observation that the more complete testing reported above showed a slightly more robust effect at oblique orientations of the test arm, as others have also noted (7,10,15). This more limited testing of six subjects unfamiliar with the aims or background of the study gave similar results (Fig.…”

Section: Parallel-lines Test Of Angle Perceptionsupporting

confidence: 59%

“…In seeking to explain these anomalous perceptions of oriented lines, most modern investigators have proposed theories based on the receptive field properties of orientation-selective neurons in V1 of subhuman primates, lateral inhibitory interactions typically playing a central part in these accounts (5,7,10,15,(26)(27)(28). In this interpretation, the closer the arms of a stimulus angle, the more likely the stimulus is to activate neighboring orientation domains in the visual cortex (or in subcortical stations) that generate mutually inhibitory interactions.…”

Section: Discussionmentioning

confidence: 99%

“…These 19th century investigations were, however, descriptive rather than experimental, and the interpretations, speculative. Despite numerous modern studies (5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15), the phenomenon of angle misperception has never been explained.…”

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confidence: 99%

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Why are angles misperceived?

Nundy

Lotto²,

Coppola³

et al. 2000

Proc. Natl. Acad. Sci. U.S.A.

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Although it has long been apparent that observers tend to overestimate the magnitude of acute angles and underestimate obtuse ones, there is no consensus about why such distortions are seen. Geometrical modeling combined with psychophysical testing of human subjects indicates that these misperceptions are the result of an empirical strategy that resolves the inherent ambiguity of angular stimuli by generating percepts of the past significance of the stimulus rather than the geometry of its retinal projection.T he fact that the subtense of any acute angle is seen as being somewhat larger than the measured angle of the stimulus, whereas the subtense of any obtuse angle is seen as being somewhat smaller, was first reported by Wundt (1) and subsequently by both Hering (2) and Helmholtz (3), all of whom surmised that these distortions might underlie some of the classical geometrical illusions (4). These 19th century investigations were, however, descriptive rather than experimental, and the interpretations, speculative. Despite numerous modern studies (5-15), the phenomenon of angle misperception has never been explained.Here we provide evidence that the systematic misperception of angle subtense is the consequence of a radically empirical strategy of perception in which the angle seen is determined by the relative frequency of the possible sources of angle projections that observers have experienced. The biological rationale for this strategy is a solution to the problem posed by the inevitable ambiguity of angular stimuli. The inability of an angle projected onto a plane to specify uniquely the source is illustrated in Fig. 1. Indeed, because space is divisible without limit, the number of possible real-world sources underlying a given retinal projection is infinite.Because the well being of an observer depends on appropriate interactions with the sources of visual stimuli, the ambiguity of retinal images has long been regarded as a central problem in vision (16). Recent studies of simultaneous brightness contrast (17,18), Mach bands (19,20),, and the perception of color (22) have all suggested that this dilemma is solved by an empirical strategy in which retinal activation triggers associations (percepts) determined by the relative frequencies of the possible sources of the stimulus in past experience. A limitation in validating this concept of vision has been the practical difficulty of quantifying the frequency distribution of the real-world sources underlying the various categories of visual experience. (This problem has also been an obstacle to psychologists who have sought to model perception in terms of Bayes' decision theorem; see ref. 23 for a recent review.) Examining the perception of oriented lines circumvents this obstacle in that the frequency distribution of the possible sources of a given retinal projection-for example, the subtense of the typical source of a given angle projected on the retina-can be computed by geometrical principles, thus providing a more concrete basis for predicting perceptual...

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Section: Parallel-lines Test Of Angle Perceptionsupporting

confidence: 59%

Section: Discussionmentioning

confidence: 99%

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Why are angles misperceived?

Nundy

Lotto²,

Coppola³

et al. 2000

Proc. Natl. Acad. Sci. U.S.A.

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“…When inducing and test lines converge and abut to form an acute angle, the lines phenomenally repulse each other in the orientation domain, an effect known as tilt contrast or acute-angle expansion. This distortion is generally reported to peak at small angles, followed by a long decline; the effect is maximized if the inducing line is either vertical or horizontal (e.g., Blakemore, Carpenter, & Georgeson, 1970;Carpenter & Blakemore, 1973; see also Bouma & Andriessen, 1970;Wenderoth, Parkinson, & White, 1979). Although the specific physiological locus of tilt-eontrast effects has been the subject of some debate (see Howard, 1982), these distortions have long been most commonly attributed to the tuning characteristics of orientation-specific cortical cells in the visual system and to lateral inhibitory interactions that occur between them (Carpenter & Blakemore, 1973; see also Blakemore, Carpenter, & Georgeson, 1970;Wenderoth, O'Connor, & Johnson, 1986).…”

Section: Discussionmentioning

confidence: 99%

Structure and strategy in encoding simplified graphs

Schiano

Tversky

1992

Mem Cogn

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Tversky and found a systematic bias toward the 45 0 line in memory for the slopes of identical lines when embedded in graphs, but not in maps, suggesting the use of a cognitive reference frame specifically for encoding meaningful graphs. The present experiments explore this issue further using the linear configurations alone as stimuli. Experiments 1 and 2 demonstrate that perception and immediate memory for the slope of a test line within orthogonal "axes" are predictable from purely structural considerations. In Experiments 3 and 4, subjects were instructed to use a diagonal-reference strategy in viewing the stimuli, which were descrfbed as "graphs" only in Experiment 3. Results for both studies showed the diagonal bias previously found only for graphs. This pattern provides converging evidence for the diagonal as a cognitive reference frame in encoding linear graphs, and demonstrates that even in highly simplified displays, strategic factors can produce encoding biases not predictable solely from stimulus structure alone.

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“…We hypothesize that orientation sensitivity is evaluated on at least two levels, with dedicated hypercolumns responding to the orientation of material that lies in the receptive field, and the only difference is the scale of the responsive wne. Induction would thus be viewed as a lateral bias of responding in the hypercolumn pool, as suggested by Bouma and Andriessen (1970). Overall induction might be a simple combination (e.g., summing) of the local and global effects.…”

Section: Discussionmentioning

confidence: 99%

Assessing the strength of angular induction using waveforms

Greene

Al-Quaddoomi

1989

Bull. Psychon. Soc.

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Angular induction is the perceptual process by which one line can bias the perceived orientation of another line or its projection. These effects are generally evaluated using long, straight lines, but the use of waveforms provides a way to vary the orientation of adjacent segments systematically. This may provide information about the nature of local and global interactions.The biological and perceptual mechanisms for judging the straightness and alignment of lines and points over long distances are not well understood. However, it is known that these attributes are affected by the relative position of the elements, as seen in classic illusions of angle and direction. For example, an oblique line segment will be misprojected across the space that lies between two horizontal or vertical parallels; this is one of the standard variants of the Poggendorff illusion. The direction of the misprojection is similar to the bending of light as it passes from air into water, but the degree of misprojection is a function of the angle of the oblique relative to each of the induction lines (Greene, 1987(Greene, , 1988. Essentially, horizontal and vertical lines have opposite effects on projection of the oblique, thus the influence of one line virtually cancels the effect of the other, even though they lie at different distances along the path of the projection.A long horizontal or vertical line segment has a greater influence on the projection than does a short segment. The present research examines the question of whether long lines derive their influence by the simple linear combination of effects from component segments. In this study, several patterns of line elements were constructed in a way that provided differential "loading" of components (e.g., a square waveform composed of successive short vertical and horizontal segments). Our goal was to evaluate the overall influence of the combined elements for inducing misprojection. MEmODVisual stimulus materials were created using an Apple Macintosh computer and a laser printer (Adobe lliustrator software). Sinusoid, square, and triangular waveforms were presented on the page as parallel bands, This work was supported in part by the Neuropsychology Foundation.Sabah Al-Quaddoomi was on a sabbatical leave at the University of Southern California from Kuwait University for the 1987-88 academic year. Correspondence may be addressed to Ernest Greene, Department of Psychology, University ofSouthem California, Los Angeles, CA 90089.as illustrated in Figure 1. Each page also contained an oblique-line segment in one of the quadrants, positioned at 30 0 to the horizontal. The general configuration was the same as for one diagonal of a Poggendorff illusion.Each of the parallel waveforms consisted of a repeating cycle of a particular amplitude and wavelength of sine, square, left-facing, and rightfacing triangular (sawtooth) waves. The amplitude and wavelength of a I-unit wave was sized to be seen as 20 min of visual angle when viewed at 46 cm. The sizing was designed to allow compariso...

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Induced changes in the perceived orientation of line segments

Cited by 96 publications

References 35 publications

Why are angles misperceived?

Why are angles misperceived?

Structure and strategy in encoding simplified graphs

Assessing the strength of angular induction using waveforms

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