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: tflew@ucsd.edu Download: evullab.org/pdf/opamBind.pdf