Theses Doctoral

How We Know When We Don't Know Enough: Neural Representations of Probabilistic Inference and Information Demand

Singletary, Nicholas Martin

In real-world settings, decision-making typically resembles a stepwise process in which one decides which information to sample before deciding to which decision option to commit. The former step is called instrumental information-seeking, and theoretical and empirical findings indicate that it is mediated by the value of information (VOI), the extent to which obtaining information increases the expected value of future actions and decisions. Economic theory predicts that to estimate VOI, decision-makers conduct a preposterior analysis in which they prospect what they would expect to know about the decision options after observing the information—or, in terms of Bayesian inference, they should prospect the future posterior probabilities. But the neural mechanisms underlying this early step of the computation of VOI remain an open question.

Therefore, to further investigate the neural substrates of instrumental information-seeking, we used functional magnetic resonance imaging (fMRI) in conjunction with two interrelated behavioral tasks in humans. With one task, we examined the demand for instrumental information, but since preposterior analysis relies on the prospection of potential future posterior beliefs, we included another task to examine how people form posterior beliefs after receiving information. We found that regions of posterior parietal cortex and occipital fusiform gyrus appear to support a preposterior analysis through the prospection of expected posterior certainty. This aligned with our finding of a region of parieto-occipital cortex that appears to support Bayesian inference by integrating the prior probability of a hypothesis with the likelihood of observed information. These results imply that parietal cortex plays a key role in Bayesian inference, supporting preposterior analysis during information-seeking in addition to Bayesian inference during categorical decision-making.


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More About This Work

Academic Units
Neurobiology and Behavior
Thesis Advisors
Gottlieb, Jacqueline
Horga, Guillermo
Ph.D., Columbia University
Published Here
July 19, 2023