Monetary loss alters perceptual thresholds and compromises future decisions via amygdala and prefrontal networks

The influence of monetary loss on decision making and choice behavior is extensively studied. However, the effect of loss on sensory perception is less explored. Here, we use conditioning in human subjects to explore how monetary loss associated with a pure tone can affect changesinperceptualthresholdsforthepreviouslyneutralstimulus.Wefoundthatloss conditioning, whencompared withneutral exposure, decreases sensitivity and increases perceptual thresholds (i.e., a relative increase inthe just-noticeable-difference). This was so even when compared with gain conditioning of comparable intensity, suggesting that the finding is related to valence. We further show that these perceptual changes are related to future decisions about stimuli that are farther away from the conditioned one (wider generalization), resulting in overall increased and irrational monetary loss for the subjects. We use functional imaging to identify the neural network whose activity correlates with the deterioration in sensitivity on an individual basis. In addition, we show that activity in theamygdala was tightly correlated with the wider behavioralgeneralization, namely, whenwrongdecisions were made.Wesuggestthat, in principle, less discrimination can be beneficial in loss scenarios, because it assures an accurate and fast response to stimuli that resemble the original stimulus and hence haveahigh likelihoodofentailingthesameoutcome.Butwhereas this canbeuseful forprimary reinforcers that can impact survival, it can also underlie wrong and costly behaviors in scenarios of contemporary life that involve secondary reinforcers.