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Title: Information integration in perceptual and value-based decisions
Author: Tsetsos, K.
ISNI:       0000 0004 2731 9732
Awarding Body: University College London (University of London)
Current Institution: University College London (University of London)
Date of Award: 2012
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Research on the psychology and neuroscience of simple, evidence-based choices has led to an impressive progress in capturing the underlying mental processes as optimal mechanisms that make the fastest decision for a specified accuracy. The idea that decision-making is an optimal process stands in contrast with findings in more complex, motivation-based decisions, focussed on multiple goals with trade-offs. Here, a number of paradoxical and puzzling choice behaviours have been revealed, posing a serious challenge to the development of a unified theory of choice. These choice anomalies have been traditionally attributed to oddities at the representation of values and little is known about the role of the process under which information is integrated towards a decision. In a series of experiments, by controlling the temporal distribution of the decision-relevant information (i.e., sensory evidence or value), I demonstrate that the characteristics of this process cause many puzzling choice paradoxes, such as temporal, risk and framing biases, as well as preference reversal. In Chapter 3, I show that information integration is characterized by temporal biases (Experimental Studies 1-2, Computational Studies 1-3). In Chapter 4, I examine the way the integration process is affected by the immediate decision context (Experimental Studies 3-4, Computational Study 4), demonstrating that prior to integration, the momentary ranking of a sample modifies its magnitude. This principle is further scrutinized in Chapter 5, where a rank-dependent accumulation model is developed (Computational Study 5). The rank-dependent model is shown to underlie preference reversal in multi-attribute choice problems and to predict that choice is sensitive, not only to the mean strength of the information, but also to its variance, favouring riskier options (Computational Study 6). This prediction is further confirmed in Chapter 6, in a number of experiments (Experimental Studies 5-7) while the direction of risk preferences is found to be modulated by the cognitive perspective induced by the task framing (Experimental Study 8). I conclude that choice arises from a deliberative process which gathers samples of decision-relevant information, weighs them according to their salience and subsequently accumulates them. The salience of a sample is determined by i) its temporal order and ii) its local ranking in the decision context, while the direction of the weighting is controlled by the task framing. The implications of this simple, microprocess model are discussed with respect to choice optimality while directions for future research, towards the development of a unified theory of choice, are suggested.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available