Extremal Edges and Gradient Cuts: New Cues to Depth and Figure-Ground Perception

2007 ◽  
Author(s):  
Stephen E. Palmer ◽  
Tandra Ghose
Keyword(s):  
Extremal Edges

scholarly journals Task set and instructions influence the weight of figural priors: A psychophysical study with extremal edges and familiar configuration

2021 ◽  
Author(s):  
Tandra Ghose ◽  
Mary A. Peterson
Keyword(s):  
Medial Temporal Lobe ◽  
Perirhinal Cortex ◽  
Shape Prior ◽  
Task Set ◽  
Cross Border ◽  
Within Subjects ◽  
Extremal Edges ◽  
Psychophysical Study ◽  
Ground Organization ◽  
Familiar Objects

AbstractIn figure–ground organization, the figure is defined as a region that is both “shaped” and “nearer.” Here we test whether changes in task set and instructions can alter the outcome of the cross-border competition between figural priors that underlies figure assignment. Extremal edge (EE), a relative distance prior, has been established as a strong figural prior when the task is to report “which side is nearer?” In three experiments using bipartite stimuli, EEs competed and cooperated with familiar configuration, a shape prior for figure assignment in a “which side is shaped?” task.” Experiment 1 showed small but significant effects of familiar configuration for displays sketching upright familiar objects, although “shaped-side” responses were predominantly determined by EEs. In Experiment 2, instructions regarding the possibility of perceiving familiar shapes were added. Now, although EE remained the dominant prior, the figure was perceived on the familiar-configuration side of the border on a significantly larger percentage of trials across all display types. In Experiment 3, both task set (nearer/shaped) and the presence versus absence of instructions emphasizing that familiar objects might be present were manipulated within subjects. With familiarity thus “primed,” effects of task set emerged when EE and familiar configuration favored opposite sides as figure. Thus, changing instructions can modulate the weighing of figural priors for shape versus distance in figure assignment in a manner that interacts with task set. Moreover, we show that the influence of familiar parts emerges in participants without medial temporal lobe/ perirhinal cortex brain damage when instructions emphasize that familiar objects might be present.

scholarly journals Surface convexity and extremal edges in depth and figure-ground perception

2005 ◽  
Vol 5 (8) ◽  
pp. 970-970 ◽  
Author(s):  
T. Ghose ◽  
S. E. Palmer
Keyword(s):  
Extremal Edges

scholarly journals Extremal edges versus other principles of figure-ground organization

2010 ◽  
Vol 10 (8) ◽  
pp. 3-3 ◽  
Author(s):  
T. Ghose ◽  
S. E. Palmer
Keyword(s):  
Extremal Edges ◽  
Ground Organization

scholarly journals Extremal edges dominate other cues to figure-ground organization

2010 ◽  
Vol 6 (6) ◽  
pp. 96-96 ◽  
Author(s):  
S. Palmer ◽  
T. Ghose
Keyword(s):  
Extremal Edges ◽  
Ground Organization

An influence of extremal edges on boundary extension

2014 ◽  
Vol 22 (4) ◽  
pp. 961-966 ◽  
Author(s):  
Ralph G. Hale ◽  
James M. Brown ◽  
Benjamin A. McDunn ◽  
Aisha P. Siddiqui
Keyword(s):  
Boundary Extension ◽  
Extremal Edges
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