Confidence drives a neural confirmation bias

Max Rollwage,Alisa Loosen,Tobias U Hauser,Stephen M Fleming,Rani Moran,Raymond J Dolan

doi:10.1038/s41467-020-16278-6

Max Rollwage, Alisa Loosen + Show 4 more

Open Access

https://doi.org/10.1038/s41467-020-16278-6

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Abstract

A prominent source of polarised and entrenched beliefs is confirmation bias, where evidence against one’s position is selectively disregarded. This effect is most starkly evident when opposing parties are highly confident in their decisions. Here we combine human magnetoencephalography (MEG) with behavioural and neural modelling to identify alterations in post-decisional processing that contribute to the phenomenon of confirmation bias. We show that holding high confidence in a decision leads to a striking modulation of post-decision neural processing, such that integration of confirmatory evidence is amplified while disconfirmatory evidence processing is abolished. We conclude that confidence shapes a selective neural gating for choice-consistent information, reducing the likelihood of changes of mind on the basis of new information. A central role for confidence in shaping the fidelity of evidence accumulation indicates that metacognitive interventions may help ameliorate this pervasive cognitive bias.

Highlights

A prominent source of polarised and entrenched beliefs is confirmation bias, where evidence against one’s position is selectively disregarded
In a first experiment we hypothesised that a confirmation bias would occur more often when people are highly confident in their original choice[24,25,26]
Consistent with our drift-diffusion models (DDMs) fits, these results indicate that a confidence-induced confirmation bias is predominantly driven by a selective accumulation of choice-consistent information

Summary

Introduction

A prominent source of polarised and entrenched beliefs is confirmation bias, where evidence against one’s position is selectively disregarded. 1234567890():,; The philosopher Bertrand Russell opined “The most savage controversies are about matters as to which there is no good evidence either way” While this view applies in some situations, even more troubling are instances where polarization and entrenchment of opinion persists in the face of contrary evidence, exemplified by debates on climate change and vaccinations. Confirmation biases have recently been demonstrated in low-level perceptual tasks[7,8,9], that are unlikely to evoke such motivated reasoning These studies indicate a source of confirmation bias may be a generic shift in the way the brain incorporates new information. We adopt such a task to study the computational and neural basis of post-decisional shifts in sensitivity to choice-consistent information. An ideal Bayesian observer should use post-decision evidence to change its mind after initial mistakes (see Supplementary Note 1 for analysis of the adaptive usage of post-decision evidence), whereas a confirmation bias would blunt this belief flexibility[13,18]

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