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Exocentric pointing in the visual field.

van Doorn A, Koenderink J, Wagemans J - Iperception (2013)

Bottom Line: Phenomenologically, such pointings show systematic deviations from veridicality of several degrees.The errors are very small in the vertical and horizontal directions, but appreciable in oblique directions.A general conclusion is that the visual field cannot be described in terms of one of the classical homogeneous spaces, or, alternatively, that the results from pointing involve mechanisms that come after geometry proper has been established.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Experimental Psychology, University of Leuven (KU Leuven), Tiensestraat 102 box 3711, B-3000 Leuven, Belgium; and Faculteit Sociale Wetenschappen, Psychologische Functieleer, Universiteit Utrecht, Heidelberglaan 2, 3584 CS Utrecht, The Netherlands; e-mail: andrea.vandoorn@telfort.nl.

ABSTRACT
"Exocentric pointing in the visual field" involves the setting of a pointer so as to visually point to a target, where both pointer and target are objects in the visual field. Phenomenologically, such pointings show systematic deviations from veridicality of several degrees. The errors are very small in the vertical and horizontal directions, but appreciable in oblique directions. The magnitude of the error is largely independent of the distance between pointer and target for stretches in the range 2-27°. A general conclusion is that the visual field cannot be described in terms of one of the classical homogeneous spaces, or, alternatively, that the results from pointing involve mechanisms that come after geometry proper has been established.

No MeSH data available.


Related in: MedlinePlus

The stimulus array with the large pointer (the red arrow), superimposed on a circular background disk filled with random Voronoi cells of 20% saturation. The texture was refreshed on each trial, in order to prevent the observer from using landmarks. The pointing direction is the direction indicated by the long tapered bi-angle (pointing upwards and slightly to the left in this example). The pointer may be rotated about the center of the background disk.
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Figure 10: The stimulus array with the large pointer (the red arrow), superimposed on a circular background disk filled with random Voronoi cells of 20% saturation. The texture was refreshed on each trial, in order to prevent the observer from using landmarks. The pointing direction is the direction indicated by the long tapered bi-angle (pointing upwards and slightly to the left in this example). The pointer may be rotated about the center of the background disk.

Mentions: The stimulus array with a target (the red circular disk), and a pointer (the red arrow), superimposed on a circular background disk filled with random Voronoi cells of 20% saturation. The texture was refreshed on each trial, in order to prevent the observer from using landmarks. In this figure (as in Figure 10), we made no attempt to reproduce the anti-aliasing used in the actual display. Pointer and target appear at random locations, the pointer in some random direction (in the example apparently quite far “off”).


Exocentric pointing in the visual field.

van Doorn A, Koenderink J, Wagemans J - Iperception (2013)

The stimulus array with the large pointer (the red arrow), superimposed on a circular background disk filled with random Voronoi cells of 20% saturation. The texture was refreshed on each trial, in order to prevent the observer from using landmarks. The pointing direction is the direction indicated by the long tapered bi-angle (pointing upwards and slightly to the left in this example). The pointer may be rotated about the center of the background disk.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4129387&req=5

Figure 10: The stimulus array with the large pointer (the red arrow), superimposed on a circular background disk filled with random Voronoi cells of 20% saturation. The texture was refreshed on each trial, in order to prevent the observer from using landmarks. The pointing direction is the direction indicated by the long tapered bi-angle (pointing upwards and slightly to the left in this example). The pointer may be rotated about the center of the background disk.
Mentions: The stimulus array with a target (the red circular disk), and a pointer (the red arrow), superimposed on a circular background disk filled with random Voronoi cells of 20% saturation. The texture was refreshed on each trial, in order to prevent the observer from using landmarks. In this figure (as in Figure 10), we made no attempt to reproduce the anti-aliasing used in the actual display. Pointer and target appear at random locations, the pointer in some random direction (in the example apparently quite far “off”).

Bottom Line: Phenomenologically, such pointings show systematic deviations from veridicality of several degrees.The errors are very small in the vertical and horizontal directions, but appreciable in oblique directions.A general conclusion is that the visual field cannot be described in terms of one of the classical homogeneous spaces, or, alternatively, that the results from pointing involve mechanisms that come after geometry proper has been established.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Experimental Psychology, University of Leuven (KU Leuven), Tiensestraat 102 box 3711, B-3000 Leuven, Belgium; and Faculteit Sociale Wetenschappen, Psychologische Functieleer, Universiteit Utrecht, Heidelberglaan 2, 3584 CS Utrecht, The Netherlands; e-mail: andrea.vandoorn@telfort.nl.

ABSTRACT
"Exocentric pointing in the visual field" involves the setting of a pointer so as to visually point to a target, where both pointer and target are objects in the visual field. Phenomenologically, such pointings show systematic deviations from veridicality of several degrees. The errors are very small in the vertical and horizontal directions, but appreciable in oblique directions. The magnitude of the error is largely independent of the distance between pointer and target for stretches in the range 2-27°. A general conclusion is that the visual field cannot be described in terms of one of the classical homogeneous spaces, or, alternatively, that the results from pointing involve mechanisms that come after geometry proper has been established.

No MeSH data available.


Related in: MedlinePlus