Repository logo
 

Fidelity of the representation of value in decision-making

Published version
Peer-reviewed

Type

Article

Change log

Authors

Bays, PM 
Dowding, BA 

Abstract

The ability to make optimal decisions depends on evaluating the expected rewards associated with different potential actions. This process is critically dependent on the fidelity with which reward value information can be maintained in the nervous system. Here we directly probe the fidelity of value representation following a standard reinforcement learning task. The results demonstrate a previously-unrecognized bias in the representation of value: extreme reward values, both low and high, are stored significantly more accurately and precisely than intermediate rewards. The symmetry between low and high rewards pertained despite substantially higher frequency of exposure to high rewards, resulting from preferential exploitation of more rewarding options. The observed variation in fidelity of value representation retrospectively predicted performance on the reinforcement learning task, demonstrating that the bias in representation has an impact on decision-making. A second experiment in which one or other extreme-valued option was omitted from the learning sequence showed that representational fidelity is primarily determined by the relative position of an encoded value on the scale of rewards experienced during learning. Both variability and guessing decreased with the reduction in the number of options, consistent with allocation of a limited representational resource. These findings have implications for existing models of reward-based learning, which typically assume defectless representation of reward value.

Description

Keywords

learning, decision making, neurons, memory, normal distribution, fractals, learning curves, working memory

Journal Title

PLOS Computational Biology

Conference Name

Journal ISSN

1553-734X
1553-7358

Volume Title

13

Publisher

PLOS
Sponsorship
Wellcome Trust (106926/Z/15/Z)
This research was supported by the Wellcome Trust (grant number 106926 to PMB).