A rodent paradigm for studying perceptual decisions under asymmetric reward

TL;DR

This study used a rat model to investigate how perceptual decisions are influenced by asymmetric rewards, revealing that rats exhibit suboptimal, stimulus-independent choice shifts possibly due to over-confidence or risk aversion.

Contribution

The paper introduces a novel rodent paradigm combining perceptual and economic decision-making, highlighting behavioral biases in reward-based perceptual choices.

Findings

Rats showed sensitivity to cue frequency and reward size.

Behavior was not optimal, with stimulus-independent choice shifts.

Subjects tended to under-shift, indicating over-confidence or risk aversion.

Abstract

Many real-life decisions involve both perceptual processes and weighing the consequences of different actions. However, the neural mechanisms underlying perceptual decisions have typically been examined separately from those underlying economic decisions. Here, we trained rats to make choices informed by both perceptual and value cues on a trial-by-trial basis. As in typical perceptual tasks, subjects were rewarded for correctly categorizing a tone relative to a learned threshold. To add an economic component, a light indicated, on each trial, whether correct responses to one side gave higher rewards than correct responses to the other side. As such, on trials with some perceptual uncertainty, it could be worthwhile to choose the unlikely option, if it had higher expected value. We found that, despite subjects sensitivity to the frequency of the cue and the reward sizes, their behavior was not optimal: subjects tended to shift their choices in a stimulus-independent way following light flashes. Moreover, subjects tended to under-shift, which could be interpreted as being over-confident in their perceptual beliefs or as being risk-averse.