Hierarchical binding & illusory conjunctions Tim F. Lew, Cory Reith, Anina Rich & Edward Vul
Response patterns from sampling!
Fixation 400ms
Objects 100ms Colors randomized Colors for objects within two locations of target unique
Response Unlimited time Randomized order & color
Task
Task
Were there part-based intrusions? Pr(Correct)=.11(.013) Pr(Incorrect Whole)=.03(.0031) Pr(2 Indep. Part)=.14(.011)
11 object types, ~22 subjects per object, 400 trials per subject
E1: Do people perceive illusory conjunctions of object parts?
Estimating whole, part & independent feature intrusions
E2: What properties help hierarchical binding?
Does part distinguishability help binding?
Binding = logPr Whole( )+Pr Part( )( )
Pr Color( )
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• Binding is hierarchical and varies across objects • Similar properties help bind features to parts & parts to wholes
Fixation 1.5s Search Feedback
• ~27 subjects per condition • 5 or 17 objects • 48 trials (2 target present/
absent X 2 object load X 2 part type X 6 displays)
• 8 of the 11 object types
Distinguishing parts helped subjects bind features to parts
and parts to wholes
Subjects more likely to recall features correctly
bound to parts
Conclusions
More binding
More similar parts
• Objects are bound hierarchically-As wholes, parts & indep. features • Feature Integration & Boolean Map theories cannot easily capture
• Ease of distinguishing parts affects hierarchical binding • Hierarchical binding may influence visual search performance
Also: Random guessing, remember one part/feature but guess other, repeat response
=Isotropic probability contour Types of errors
Background Feature Integration & Boolean Map theories Location-focused attention binds features to objects
Observe Recall Feature illusory
conjunction Whole objects
Hierarchical binding Do people also perceive illusory
conjunctions of object parts?
Part illusory conjunction
Contact: [email protected] Download: evullab.org/pdf/opamBind.pdf