Attention, Probability and Fatigue in Decision Making (Stress, Arousal, Narrowing)
The quality of information search conducted in complex decision environments is a key determinant of overall decision performance. Humans, as limited processors of information, are forced to select one set of cues over another, upon which they will ultimately base their decision. Attention is a central element in this selective process. Humans tend to disproportionately allocate their attention to highly probable or salient information, irrespective of that information's location in the decision environment. The purpose of this study was to investigate the relationship between probability and location in the visual modality when information was biased in favor of the visual periphery. Sixteen right-handed male volunteers performed a choice reaction time (RT) task to lights located at 0, 3, 20, 50, and 80 degrees to their right. Following a practice session that included simple RT trials (simple RT was also tested at the end of the experiment) four levels of probability were administered; one per day across a four day testing regime. The probabilities were: .50, .60, .70, and .80. A testing day was divided into four blocks with one, non-central, light location (e.g., 3, 20, 50, or 80 degrees) being paired with the 0 degree location in each block. A subject completed 180 trials in each block. An incomplete latin square procedure was employed to counterbalance probability and trial blocks. Fixation was controlled with a centrally located light. Results indicated that as probability increased, RT to the four non-central lights decreased. No decline in RT performance was observed, however, at the central location until the .80 condition. An unexpected finding was discovered in the analysis of the simple RT data. RT to the 0 and 3 degree locations was significantly slower than to the 20 and 50 degree locations. It was speculated that these effects were influenced by masking. Trial blocks were analyzed to investigate possible fatigue induced attentional narrowing. Although a significant main effect was found for blocks, no evidence was discovered to suggest that attention became increasingly selective under fatigue.
University of Illinois - Urbana-Champaign
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University of Illinois at Urbana-Champaign