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Orientation tuning of a two-stimulus afterimage: Implications for theories of filling-in.

Van Horn DR, Francis G - Adv Cogn Psychol (2008)

Bottom Line: From the analysis, we show that the model must predict a rapid drop in afterimage occurrence as the gratings deviate from orthogonal.We then report on 2 experiments that test the properties of the model and find that the experimental data are strikingly different from the model predictions.From these discrepancies we identify the key deficits of the current version of the model.

View Article: PubMed Central - PubMed

Affiliation: Psychological Sciences, Purdue University,West Lafayette, IN, USA.

ABSTRACT
Sequential viewing of 2 orthogonally related gratings produces an afterimage related to the firstgrating (Vidyasagar, Buzas, Kisyarday, & Eysel, 1999; Francis & Rothmayer, 2003). We investigated how the appearance of the afterimage depended on the relative orientations of the 2 stimulus gratings. We firstanalyzethetheoretical explanation of the appearance of the afterimage that was proposed by Francis and Rothameyer (2003). From the analysis, we show that the model must predict a rapid drop in afterimage occurrence as the gratings deviate from orthogonal. We also show that the model predicts that the shape of the afterimage should always be orthogonal to the second grating. We then report on 2 experiments that test the properties of the model and find that the experimental data are strikingly different from the model predictions. From these discrepancies we identify the key deficits of the current version of the model.

No MeSH data available.


The sequence of images for a simulated trial in Experiment 1. The							orientation of the first stimulus varied from trial to trial. Any after							images were measured during the second blank frame.
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Figure 4: The sequence of images for a simulated trial in Experiment 1. The orientation of the first stimulus varied from trial to trial. Any after images were measured during the second blank frame.

Mentions: All of the model simulations used the same equations and parameters as Wede and Francis (2006) . Figure 4 shows the sequence of stimuli presented to the model. S1 was a bar grating, placed within a circular aperture and presented for one simulated second. On different trials, S1 was rotated relative to S2. This was followed by a blank screen for 100 ms. S2 was always oriented horizontally and presented for a total of 2 s. To minimize color adaptation to S2, the bar grating flickered with an alternating phase shifted version of the grating (black and white bars changed to their opposite color). S2 was followed by a blank screen for 2 s, and at the end of the blank screen the model’s predicted percept was computed at the filling-in stage of the model.


Orientation tuning of a two-stimulus afterimage: Implications for theories of filling-in.

Van Horn DR, Francis G - Adv Cogn Psychol (2008)

The sequence of images for a simulated trial in Experiment 1. The							orientation of the first stimulus varied from trial to trial. Any after							images were measured during the second blank frame.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2864993&req=5

Figure 4: The sequence of images for a simulated trial in Experiment 1. The orientation of the first stimulus varied from trial to trial. Any after images were measured during the second blank frame.
Mentions: All of the model simulations used the same equations and parameters as Wede and Francis (2006) . Figure 4 shows the sequence of stimuli presented to the model. S1 was a bar grating, placed within a circular aperture and presented for one simulated second. On different trials, S1 was rotated relative to S2. This was followed by a blank screen for 100 ms. S2 was always oriented horizontally and presented for a total of 2 s. To minimize color adaptation to S2, the bar grating flickered with an alternating phase shifted version of the grating (black and white bars changed to their opposite color). S2 was followed by a blank screen for 2 s, and at the end of the blank screen the model’s predicted percept was computed at the filling-in stage of the model.

Bottom Line: From the analysis, we show that the model must predict a rapid drop in afterimage occurrence as the gratings deviate from orthogonal.We then report on 2 experiments that test the properties of the model and find that the experimental data are strikingly different from the model predictions.From these discrepancies we identify the key deficits of the current version of the model.

View Article: PubMed Central - PubMed

Affiliation: Psychological Sciences, Purdue University,West Lafayette, IN, USA.

ABSTRACT
Sequential viewing of 2 orthogonally related gratings produces an afterimage related to the firstgrating (Vidyasagar, Buzas, Kisyarday, & Eysel, 1999; Francis & Rothmayer, 2003). We investigated how the appearance of the afterimage depended on the relative orientations of the 2 stimulus gratings. We firstanalyzethetheoretical explanation of the appearance of the afterimage that was proposed by Francis and Rothameyer (2003). From the analysis, we show that the model must predict a rapid drop in afterimage occurrence as the gratings deviate from orthogonal. We also show that the model predicts that the shape of the afterimage should always be orthogonal to the second grating. We then report on 2 experiments that test the properties of the model and find that the experimental data are strikingly different from the model predictions. From these discrepancies we identify the key deficits of the current version of the model.

No MeSH data available.