Confirmation bias through selective readout of information encoded in human parietal cortex

Area of Science:

• Cognitive Neuroscience
• Decision-Making Science

Background:

• Decision-makers exhibit confirmation bias, selectively processing evidence aligned with existing beliefs.
• The neural basis of this bias, whether in evidence encoding or utilization, remains unclear.

Purpose of the Study:

• To investigate whether confirmation biases stem from biased sensory evidence encoding or biased utilization of encoded evidence.
• To determine how the brain processes subsequent evidence based on prior choices.

Main Methods:

• Magnetoencephalography (MEG) measured cortical activity in human participants.
• Participants estimated visual-spatial evidence sources and made category judgments.
• Subsequent evidence processing was analyzed based on its consistency with prior choices.

Main Results:

• Evidence encoded in parietal cortex contributed more to estimations when consistent with the prior choice.
• Information contradicting pre-existing beliefs had less impact on behavior, despite accurate neural encoding.
• Subsequent evidence processing was modulated by the consistency with the chosen category.

Conclusions:

• Confirmation biases are linked to the utilization of encoded evidence, not its initial encoding.
• Neural evidence contradicting prior beliefs is underutilized in behavioral decision-making.
• Deliberative control mechanisms may be necessary to overcome confirmation biases.