CCNCS Seminar Details
Unveiling the mechanism of value integration and preference formation
|Date/Time:||Wednesday 24 October 2012, 4.15pm|
Research on the neurocognitive bases of decision-making has proceeded in two parallel but distinct streams. On the one hand, perceptual decision-making is concerned with how observers detect, discriminate, and categorize noisy sensory information. On the other pole, economic decision-making explores how options are selected on the basis of their value. While perceptual decisions appear to approximate statistical optimality, economic decisions often violate the rational norms. This discrepancy poses a serious challenge in the development of a unified theory of choice. I take as starting point that in both cases the cognitive system needs to integrate samples of relevant information (i.e. sensory evidence in perceptual decisions and subjective values in economic decisions) in order to reach a decision. However, while in perceptual experiments the flow of sensory information, can be under the full control of the experimenter, preference tasks provide little control of the moment-by-moment process of value sampling and integration. This limitation impedes the investigation of the mechanism under which people attend to and integrate subjective values. I will present a novel preference paradigm, called "value psychophysics", at the interface of classical psychophysics and economic decisions. Participants in this task view simultaneously two or three rapidly varying sequences of numerical values, described as stock market values or slot machines' past payouts. At the end of the presentation, they choose the sequence that they think has the highest overall value. Using this paradigm, a series of choice paradoxes, such as temporal, risk, and framing biases as well as preference reversals are obtained. I will demonstrate that these choice anomalies fall out from a simple integration mechanism, which weighs the samples of values by their salience. The salience of each sample depends on its momentary rank within the decision context and, furthermore, is determined by the decision frame (i.e. accept vs. reject). I will conclude that known choice anomalies arise from the microstructure of the value integration process; and I will claim that similar biases might exist in purely perceptual decisions.