Here's how brain calculates confidence

A new study has found that our brains are constantly processing data to make statistical assessments that translate into the feeling we call confidence.

This feeling of confidence is central to decision making and, despite ample evidence of human fallibility, the subjective feeling relies on objective calculations.

"The feeling ultimately relies on the same statistical computations a computer would make," says lead author Adam Kepecs of the Cold Spring Harbor Laboratory.

The development of a model for confidence is a first step towards Kepecs's ultimate goal to find out where this inner statistician sits in the brain and how it does its data processing.

Kepecs's model for human confidence stood up to a follow-on experiment in which participants answered questions comparing the populations of various countries. Unlike the perceptual test, this one had the added complexity of each participant's individual knowledge base.

Even human foibles, such as being overconfident in the face of hard choices with poor data or under-confident when facing easy choices, were consistent with Kepecs's model. "This subjective feeling of confidence relies on a statistical computation," Kepecs says. "Confidence is not a heuristic or a shortcut."

Kepecs plans to use his model of confidence as a foothold for finding the seat of confidence in the brain and understanding its neural circuitry. "Having a theory about confidence is a required first step to figure out how the brain actually does it, how nerve cells perform this process," he says.

The study appears in Neuron.