The timing of confidence computations in human prefrontal cortex

Area of Science:

• Neuroscience
• Cognitive Science
• Computational Psychiatry

Background:

• Understanding the timing of confidence computations is crucial for elucidating the neural and computational underpinnings of metacognition.
• Previous research has identified neural correlates of confidence judgments but has largely overlooked the temporal dynamics of these computations.

Purpose of the Study:

• To investigate the temporal window during which confidence computations occur in the human brain.
• To determine the causal role of the right dorsolateral prefrontal cortex (DLPFC) in confidence generation and its timing.

Main Methods:

• Applied single-pulse transcranial magnetic stimulation (TMS) to the right DLPFC or vertex (control) at various times after visual stimulus presentation.
• Participants performed an orientation judgment task and provided confidence ratings for their decisions.
• Analyzed the effects of TMS timing and location on accuracy, confidence, and metacognitive efficiency.

Main Results:

• TMS applied to the right DLPFC, but not the vertex, significantly increased subjective confidence ratings.
• This increase in confidence occurred without altering objective accuracy or metacognitive efficiency.
• The effect of right DLPFC TMS on confidence was observed for pulses delivered between 200 and 500 milliseconds post-stimulus onset.

Conclusions:

• Confidence computations involve a protracted temporal window, extending into the period before a perceptual decision is fully finalized.
• The right DLPFC plays a causal role in modulating confidence during this broad temporal window.
• These findings provide critical constraints for computational models of confidence generation and metacognition.