Limits...
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.


Results from Experiment 2. (a) The model predicts a strong afterimage							when S2 differs by 90 degrees from either of the components of S1. Small							deviations from orthogonality lead to large decreases in the strength of							the afterimage, (b) the experimental data show that reports of							horizontal and vertical afterimages occur for rotations where the model							predicts weak afterimages; moreover, the data show that observers report							seeing both horizontal and vertical components of the afterimage for							intermediate rotations.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC2864993&req=5

Figure 9: Results from Experiment 2. (a) The model predicts a strong afterimage when S2 differs by 90 degrees from either of the components of S1. Small deviations from orthogonality lead to large decreases in the strength of the afterimage, (b) the experimental data show that reports of horizontal and vertical afterimages occur for rotations where the model predicts weak afterimages; moreover, the data show that observers report seeing both horizontal and vertical components of the afterimage for intermediate rotations.

Mentions: Figure 9a plots a measure of the strength of the afterimage in the model as a function of the rotation of S1. This strength calculation does not consider the shape of the afterimage percept, but as shown below the model makes a straightforward prediction regarding the after-image shape. The results for rotations up to 45° are similar as those in Figure 5a. There is a rapid drop in afterimage strength. There is a slight upturn in afterimage strength at 45° and then a symmetrical increase in afterimage strength for larger rotations. The symmetry occurs because the pattern of S1 repeats after a 45° rotation. The upturn at 45° occurs because when the pattern is at 45° the intersections of the crossed bars line up vertically.


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

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

Results from Experiment 2. (a) The model predicts a strong afterimage							when S2 differs by 90 degrees from either of the components of S1. Small							deviations from orthogonality lead to large decreases in the strength of							the afterimage, (b) the experimental data show that reports of							horizontal and vertical afterimages occur for rotations where the model							predicts weak afterimages; moreover, the data show that observers report							seeing both horizontal and vertical components of the afterimage for							intermediate rotations.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 9: Results from Experiment 2. (a) The model predicts a strong afterimage when S2 differs by 90 degrees from either of the components of S1. Small deviations from orthogonality lead to large decreases in the strength of the afterimage, (b) the experimental data show that reports of horizontal and vertical afterimages occur for rotations where the model predicts weak afterimages; moreover, the data show that observers report seeing both horizontal and vertical components of the afterimage for intermediate rotations.
Mentions: Figure 9a plots a measure of the strength of the afterimage in the model as a function of the rotation of S1. This strength calculation does not consider the shape of the afterimage percept, but as shown below the model makes a straightforward prediction regarding the after-image shape. The results for rotations up to 45° are similar as those in Figure 5a. There is a rapid drop in afterimage strength. There is a slight upturn in afterimage strength at 45° and then a symmetrical increase in afterimage strength for larger rotations. The symmetry occurs because the pattern of S1 repeats after a 45° rotation. The upturn at 45° occurs because when the pattern is at 45° the intersections of the crossed bars line up vertically.

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.