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Transcript of Vwm20091013
The Comparison of Visual Working Memory Representations With
Perceptual Inputs
Hyun, Woodman, Vogel, Hollingworth, & Luck
JEP: HPP 2009
• Changes can be detected by means of an unlimited-capacity comparison process, which can be used to direct covert and overt attention but that manual responses depend on a limited-capacity process.
• The unlimited-capacity comparison process can be limited to specificfeature dimensions.
Visual Working Memory (VWM)
• Working memory : A memory system that holds information temporarily so that it can be used in the service of some task.
• Visual Working Memory Representations & Perceptual Inputs
The Change Detection Task
• Commonly used to study the nature of the VWM representations.
1. form a perceptual representation→2. transformed into a stable working memory
representation →3. maintained across the retention interval →4. be compared with the sensory input →5. generate a single two-alternative response
Prior Research on Perceptual Comparison
• Taylor (1976)
A Theoretical Framework
• The change detection task can be considered a type of visual search task.
• three issues1. limited- or unlimited-capacity perceptual process2. presence of a feature & absence of a feature.3. voluntarily or involuntarily attracted
• three subhypotheses1. means of an unlimited capacity comparison process2. comparison asymmetry (search asymmetry effect)3. a shift of attention to the changed item (voluntary)
• key difference• the initial comparison process is unlimited in
capacity in two important ways
Experiment 1: Relating Change Detection to Perceptual Comparison
Experiment 2: Allocation of Covert Attention to the Changed Item
Experiment 3: Allocation of Overt Attention to the Changed Item
Experiments 4A and 4B: Effects of Set Size on Manual RTs
Experiment 5: Do Changes Attract Attention Involuntarily?
Overview of the Present Study
• RT increases much more steeply as a function of set size in the any-sameness task. (Exp1)
• The presence of a changed item in the test array in the any-difference task leads to a shift of attention to the location of this item. (Exp2&3)
Overview of the Present Study
• a limited-capacity process is interposed between the shift of attention and the observer’s button-press response. (Exp4A&4B)
• The shift of attention to a changed item is under voluntary control. (Exp5)
General Discussion
• Similarities Between Change Detection and Visual Search
• Limited- and Unlimited-Capacity Comparison Processes in Change Detection