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Choice-making in the brain
MANHATTAN, KAN. -- The next time you are frustrated by someone who says, "I'm of two minds about this," at least you will know why. The latest research conducted by Kip Smith, an assistant professor of psychology at Kansas State University, may be able to explain why people often can't make up their minds. Smith's current study focuses on which parts of the brain are used in the decision-making process.
"We're of at least two minds," Smith said. "This research shows the brain is not a single entity. There is not a single executive decision-making mechanism there."
Smith's research has resulted in neuroimages of the parts of the brain used in different types of choices. Smith said there are two systems for making decisions in the brain: deliberative and emotional. Deliberative systems, also referred to as calculation areas, utilize parts of the brain related to mathematics and rational decisions. Emotional systems utilize older, more primal parts of the brain.
According to Smith, individual behavior is affected by attitudes about payoffs, such as gains and losses, in addition to beliefs about outcomes, such as risk and ambiguity. During the experiments, the brain activity of participants was measured by positron emission tomography. The research demonstrates the relationship between brain activity and observed choices. Smith's results allowed him to create images of the parts of the brain used for risk, ambiguity, gains and losses with decision making in the experiment.
Smith said some of the results were surprising. "We thought that risky losses would be processed by the part of the brain that responds to fear, but they were dealt with in a fairly rational manner," he said. Also, the deliberative areas of the brain did not show high usage with decisions relating to risky gains. "It could be that the emotional areas overwhelm the calculation areas. The results are correlational, because it's not a completely controlled experiment."
Smith's results were published in the June 2002 issue of Management Science in the article "Neuronal Substrates for Choice under Ambiguity, Risk, Gains and Losses." The paper was co-authored by John Dickhaut, University of Minnesota; Kevin McCabe, George Mason University; and Jose V. Pardo, Veterans Affairs Medical Center and the University of Minnesota. A second paper, "The Impact of the Certainty Context on the Process of Choice," is forthcoming in the Proceedings of the National Academy of Sciences. Dickhaut, McCabe and Pardo, as well as Aldo Rustichini, University of Minnesota, and Jennifer C. Nagode, Veterans Affairs Medical Center and the University of Minnesota, co-authored the second paper.
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