Cost-sensitive Bayesian control policy in human active sensing
Journal
Frontiers in Human Neuroscience
Journal Volume
8
Journal Issue
DEC
Date Issued
2014
Author(s)
Abstract
An important but poorly understood aspect of sensory processing is the role of active sensing, the use of self-motion such as eye or head movements to focus sensing resources on the most rewarding or informative aspects of the sensory environment. Here, we present behavioral data from a visual search experiment, as well as a Bayesian model of within-trial dynamics of sensory processing and eye movements. Within this Bayes-optimal inference and control framework, which we call C-DAC (Context-Dependent Active Controller), various types of behavioral costs, such as temporal delay, response error, and sensor repositioning cost, are explicitly minimized. This contrasts with previously proposed algorithms that optimize abstract statistical objectives such as anticipated information gain (Infomax) (Butko and Movellan, 2010) and expected posterior maximum (greedy MAP) (Najemnik and Geisler, 2005). We find that C-DAC captures human visual search dynamics better than previous models, in particular a certain form of "confirmation bias” apparent in the way human subjects utilize prior knowledge about the spatial distribution of the search target to improve search speed and accuracy. We also examine several computationally efficient approximations to C-DAC that may present biologically more plausible accounts of the neural computations underlying active sensing, as well as practical tools for solving active sensing problems in engineering applications. To summarize, this paper makes the following key contributions: human visual search behavioral data, a context-sensitive Bayesian active sensing model, a comparative study between different models of human active sensing, and a family of efficient approximations to the optimal model. © 2014 Ahmad, Huang and Yu.
Subjects
Active sensing; Bayesian model; Markov decision processes; Overt attention; Saccadic eye movements; Visual search
Other Subjects
accuracy; algorithm; Article; Bayes theorem; comparative study; conceptual framework; controlled study; dynamics; eye movement; knowledge; mathematical computing; neurophysiology; policy; sensory system; statistical model; visual system function
Type
journal article