Mike Byrne, Assoc Prof. Psy & Comp Sci, Rice University

 

Mike Byrne, Assoc Prof. Psy & Comp Sci, Rice University

Sage 4101

March 4, 2009 12:00 PM - 1:30 PM

Abstract:One of the critical decisions faced by the human visual system multiple times every second is what to attend to next.  Because this is such an important question, the literature contains many models of parts of this process, but virtually none that are part of an integrated cognitive system.  To remedy this, Byrne (2006) proposed an extension to the ACT-R visual system based on information theory.    This system incorporates both bottom-up visual factors (e.g., if there is only one green object on a display of blue objects, it tends to pop out) as well as top-down factors (e.g., if the cognitive system expects the next relevant item to be on the left, the visual system is more likely to select items on the left).  We report on new experiments which test fundamental assumptions of this framework and present model fits to these results.  The model captures not only the distractor ratio effect and asymmetries between target-present and target-absent trials, but also the counter-intuitive result that in most cases, reducing the number of objects on the display (by as much as 30 items) produced no improvement in visual search time.  Future directions include a getting a more thorough understanding of the temporal dynamics of salience, understanding the relationship with eye movements, and testing the model in more complex visual environments and with tasks containing stronger top-down influences, such as locating information on ballots and cockpit displays.  

Local Theories Versus Comprehensive Architectures

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