RT Journal Article
SR Electronic
T1 Stochastic models of evidence accumulation in changing environments
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 019398
DO 10.1101/019398
A1 Alan Veliz-Cuba
A1 Zachary P. Kilpatrick
A1 Krešimir Josić
YR 2015
UL http://biorxiv.org/content/early/2015/05/16/019398.abstract
AB Organisms and ecological groups accumulate evidence to make decisions. Classic experiments and theoretical studies have explored decisions between alternatives when the correct choice is fixed during a trial. However, the natural world constantly changes. Using sequential analysis we derive equations for the likelihood of different choices, when the correct option changes in time. Our analysis shows that ideal observers discount prior evidence at a rate determined by the volatility of the environment. Nondimensionalization shows that the dynamics of evidence accumulation is governed solely by the information gained over an average environmental epoch. A plausible neural implementation of an optimal observer in a changing environment shows that, in contrast with previous models, neural populations representing alternate choices are coupled through excitation.