Adaptation for Discrimination
Adaptation for Discrimination
Light reflected = r * I
Light reflected = r * I
Adaptation for Discrimination
Adaptation for Discrimination
Adaptation for Discrimination
DIT1
DIT2
DIT1
Discrimination Thresholds
Response Function
DIT1
DIT2
Pedestal Contrast
Discrimination Thresholds
Boynton et al., 1999
Discrimination Thresholds
Discrimination Thresholds
Adaptation for Appearance
Light reflected = r * I
Light reflected = r * I
Adaptation for Appearance
Adaptation for Appearance
Adaptation for Appearance
See Hillis and Brainard (2005; under review)
Discrimination Thresholds
See Hillis and Brainard (2005; under review)
Discrimination Thresholds
See Hillis and Brainard (2005; under review)
Thresholds & Appearance
See Hillis and Brainard (2005; under review)
See Hillis and Brainard (2005; under review)
Summary
• Both threshold and appearance measurements can be
linked (by hypothesis) to an underlying response function.
• Studying change in response function with viewing context
is one way to characterize adaptation.
• For simple context changes (intensity of uniform
backgrounds, unstructured contrast), both threshold and
appearance data are consistent with a common mechanism
of adaptation. [This is not true in general.]
“SHADOW”
x
x
“PAINT”
x
x
(Adopted, with permission, from Adelson’s checkerboard illusion
)
“Shadow”
“Paint”
“Shadow”
“Paint”