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Grouping based feature attribution in metacontrast masking.

Otto TU - Adv Cogn Psychol (2008)

Bottom Line: Still, some features of the target can be perceived within the mask.Usually, these rare cases of feature mis-localizations are assumed to reflect errors of the visual system.To the contrary, I will show that feature "mis-localizations" in metacontrast masking follow rules of motion grouping and, hence, should be viewed as part of a systematic feature attribution process.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Psychophysics, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), Switzerland.

ABSTRACT
The visibility of a target can be strongly suppressed by metacontrast masking. Still, some features of the target can be perceived within the mask. Usually, these rare cases of feature mis-localizations are assumed to reflect errors of the visual system. To the contrary, I will show that feature "mis-localizations" in metacontrast masking follow rules of motion grouping and, hence, should be viewed as part of a systematic feature attribution process.

No MeSH data available.


Related in: MedlinePlus

Sequential metacontrast. The central target line is followed by a sequence of						flanking lines, here by two streams of lines shifting to the left. (A)						Observers were asked to report the offset of the attended left stream of						lines. If only the target line is randomly offset to the left or right, a						corresponding offset direction is reported pre-dominantly. (B, C) A second						offset in the opposite direction is presented either at the right (B) or						left line (C) in the third frame. Performance, compared to A, is changed if						the second offset is presented to the left line (C). Performance is not						changed in B although the second offset is presented at the same spatial						position as the target. (D-F) Stimuli are exactly the same as in A-C,						respectively. Observers were asked to attend to the right stream of lines.						Similar to A, if only the target line is offset, a corresponding offset is						reported (D). However, feature integration in E and F is reversed compared						to B and C. Performance compared to D is changed by the offset presented at						the right line (E), whereas performance is only slightly changed by the						second offset presented at the left line (F). These findings indicate that a						small leakage across motion steams is possible. Still, features are						basically integrated within the attended motion streams. A, B, D, and E						adapted from Otto et al. (2006) with permission, ©ARVO.
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Figure 2: Sequential metacontrast. The central target line is followed by a sequence of flanking lines, here by two streams of lines shifting to the left. (A) Observers were asked to report the offset of the attended left stream of lines. If only the target line is randomly offset to the left or right, a corresponding offset direction is reported pre-dominantly. (B, C) A second offset in the opposite direction is presented either at the right (B) or left line (C) in the third frame. Performance, compared to A, is changed if the second offset is presented to the left line (C). Performance is not changed in B although the second offset is presented at the same spatial position as the target. (D-F) Stimuli are exactly the same as in A-C, respectively. Observers were asked to attend to the right stream of lines. Similar to A, if only the target line is offset, a corresponding offset is reported (D). However, feature integration in E and F is reversed compared to B and C. Performance compared to D is changed by the offset presented at the right line (E), whereas performance is only slightly changed by the second offset presented at the left line (F). These findings indicate that a small leakage across motion steams is possible. Still, features are basically integrated within the attended motion streams. A, B, D, and E adapted from Otto et al. (2006) with permission, ©ARVO.

Mentions: Surprisingly, when the target line itself is invisible, some features of the suppressed target can be perceived as mis-localized within the flanking lines (Figure 2B). Werner (1935) was the first to observe feature mis-localizations in metacontrast masking. When he presented a polygon followed by a surrounding ring, the ring appeared as a “ring with teeth” (Werner, 1935, p. 58). Similarly, there are other anecdotal reports of feature mis-localization (e.g., Hogben & Di Lollo, 1984; Stewart & Purcell, 1970; Stoper & Banffy, 1977), but only a few systematic studies (Hofer, Walder, & Groner, 1989; Wilson & Johnson, 1985). It has been shown that not only contour features of a target can be inherited but also brightness (Burr, 1984; Toch, 1956), and that the duration of an invisible target can contribute to the perceived duration of the following mask (Scharlau, this volume). Moreover, feature mis-localizations can occur in pattern masking (Herzog & Koch, 2001). In summary, although the visibility of a target can be strongly reduced in metacontrast masking, several features of the target can be perceived within the mask. Here, the question arises, if the target itself is suppressed, how are these features processed?


Grouping based feature attribution in metacontrast masking.

Otto TU - Adv Cogn Psychol (2008)

Sequential metacontrast. The central target line is followed by a sequence of						flanking lines, here by two streams of lines shifting to the left. (A)						Observers were asked to report the offset of the attended left stream of						lines. If only the target line is randomly offset to the left or right, a						corresponding offset direction is reported pre-dominantly. (B, C) A second						offset in the opposite direction is presented either at the right (B) or						left line (C) in the third frame. Performance, compared to A, is changed if						the second offset is presented to the left line (C). Performance is not						changed in B although the second offset is presented at the same spatial						position as the target. (D-F) Stimuli are exactly the same as in A-C,						respectively. Observers were asked to attend to the right stream of lines.						Similar to A, if only the target line is offset, a corresponding offset is						reported (D). However, feature integration in E and F is reversed compared						to B and C. Performance compared to D is changed by the offset presented at						the right line (E), whereas performance is only slightly changed by the						second offset presented at the left line (F). These findings indicate that a						small leakage across motion steams is possible. Still, features are						basically integrated within the attended motion streams. A, B, D, and E						adapted from Otto et al. (2006) with permission, ©ARVO.
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Related In: Results  -  Collection

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Figure 2: Sequential metacontrast. The central target line is followed by a sequence of flanking lines, here by two streams of lines shifting to the left. (A) Observers were asked to report the offset of the attended left stream of lines. If only the target line is randomly offset to the left or right, a corresponding offset direction is reported pre-dominantly. (B, C) A second offset in the opposite direction is presented either at the right (B) or left line (C) in the third frame. Performance, compared to A, is changed if the second offset is presented to the left line (C). Performance is not changed in B although the second offset is presented at the same spatial position as the target. (D-F) Stimuli are exactly the same as in A-C, respectively. Observers were asked to attend to the right stream of lines. Similar to A, if only the target line is offset, a corresponding offset is reported (D). However, feature integration in E and F is reversed compared to B and C. Performance compared to D is changed by the offset presented at the right line (E), whereas performance is only slightly changed by the second offset presented at the left line (F). These findings indicate that a small leakage across motion steams is possible. Still, features are basically integrated within the attended motion streams. A, B, D, and E adapted from Otto et al. (2006) with permission, ©ARVO.
Mentions: Surprisingly, when the target line itself is invisible, some features of the suppressed target can be perceived as mis-localized within the flanking lines (Figure 2B). Werner (1935) was the first to observe feature mis-localizations in metacontrast masking. When he presented a polygon followed by a surrounding ring, the ring appeared as a “ring with teeth” (Werner, 1935, p. 58). Similarly, there are other anecdotal reports of feature mis-localization (e.g., Hogben & Di Lollo, 1984; Stewart & Purcell, 1970; Stoper & Banffy, 1977), but only a few systematic studies (Hofer, Walder, & Groner, 1989; Wilson & Johnson, 1985). It has been shown that not only contour features of a target can be inherited but also brightness (Burr, 1984; Toch, 1956), and that the duration of an invisible target can contribute to the perceived duration of the following mask (Scharlau, this volume). Moreover, feature mis-localizations can occur in pattern masking (Herzog & Koch, 2001). In summary, although the visibility of a target can be strongly reduced in metacontrast masking, several features of the target can be perceived within the mask. Here, the question arises, if the target itself is suppressed, how are these features processed?

Bottom Line: Still, some features of the target can be perceived within the mask.Usually, these rare cases of feature mis-localizations are assumed to reflect errors of the visual system.To the contrary, I will show that feature "mis-localizations" in metacontrast masking follow rules of motion grouping and, hence, should be viewed as part of a systematic feature attribution process.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Psychophysics, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), Switzerland.

ABSTRACT
The visibility of a target can be strongly suppressed by metacontrast masking. Still, some features of the target can be perceived within the mask. Usually, these rare cases of feature mis-localizations are assumed to reflect errors of the visual system. To the contrary, I will show that feature "mis-localizations" in metacontrast masking follow rules of motion grouping and, hence, should be viewed as part of a systematic feature attribution process.

No MeSH data available.


Related in: MedlinePlus