Michel Brudzinski/ Graduate Students

 

Michel Brudzinski/ Graduate Students

Sage 4101

November 18, 2009 12:00 PM - 1:30 PM

 Abstract: Research conducted in our laboratory has demonstrated that the human cognitive system can flexibly utilize internal (memory) or external (perceptual) sources of information, depending on task conditions. Certain conditions bias the cognitive system towards the use of external sources and a reliance on cues from the environmental and task contexts to control goal-directed behavior.Multitasking, which can be described as the near simultaneous pursuit of multiple goals, tends to create such conditions. Several characteristics of dynamic multitasking situations create this bias:(1)  The changing state of dynamic tasks decreases the accuracy of older perceptual information stored in memory(2)  The decreased retrieval probability and increased retrieval latency that result from the decay of memory activation that occurs while the system is pursuing other goals(3)  The number of goals and problem states that must be maintained in working memory approaches or exceeds working memory capacityThese conditions increase the time costs associated with internal sources for action selection and task coordination. The cognitive system instead relies on external sources of cognitive control that invoke automatic processes, thus allowing multiple goals to be pursued nearly simultaneously. These automatic processes are based on learned associations. The visual properties of objects in the environment develop associations with goals (task cues) and means to attain goals (affordances). The perception of known objects, or their visual properties, spreads activation to associated goals and actions. Increased activation, from this priming, increases the likelihood that these goals and actions will be selected. A modification to the ACT-R architecture is proposed to model both the learning and behavioral effects of contextual task cues. Cues are learned by storing time-locked, cross-modal, representations of the cognitive system's internal states. Statistical regularities are analyzed to determine the strength of priming from contents of the current context to potential goals and actions. Goals and actions are then selected based on their activation values. In this way, external sources, such as contextual task cues, can control action selection and task coordination during multitasking behavior.
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