Why mistakes slow us down decoded?

Washington :Are you taking more time to make decisions after committing a mistake? New research has found that it is due to a combination of changes in the brain that slow us down after mistakes.

Taking more time to make decisions after a mistake arises from a mixture of adaptive neural mechanisms that improve the accuracy and maladaptive mechanisms that reduce it, the study by researchers from New York University (NYU) has found.

“Our research reveals that a combination of changes in the brain slow us down after mistakes. One gathers more information for the decision to prevent repeating the same mistake again,” said Braden Purcell, a co-author of the study.

“A second change reduces the quality of evidence we obtain, which decreases the likelihood we will make an accurate choice,” said Purcell.

Researchers sought to address the question of what neurological processes occur when humans slow down after mistakes, a phenomenon called post-error slowing (PES).

They conducted a series of experiments involving monkeys and humans. Both watched a field of noisy moving dots on a computer screen and reported their decision about the net direction of motion with their gaze.

The experimenters controlled the difficulty of each decision with the proportion of dots that moved together in a single direction – for instance, a large proportion of dots moving to the right provided very strong evidence for a rightward choice, but a small proportion provided only weak evidence.

Humans and monkeys showed strikingly similar behaviour. After errors, both slowed down the decision-making process, but the pattern of slowing depended on the difficulty of the decision, researchers said.

Slowing was maximum for more difficult decisions, suggesting longer accumulation of information. However, the overall accuracy of their choices did not change, indicating the quality of accumulated sensory information was lower.

Brain activity observed from the monkeys while they performed the task shed light on what was happening in the brain.

The researchers analysed neural responses from a region of parietal cortex involved in accumulating information in their task.

During decision making, these neurons represent evidence accumulation by increasing their activity over time at a rate that depends on the quality of evidence.

Specifically, stronger motion leads to faster ramping and weaker motion leads to slower ramping, researchers said.

After mistakes, the exact same motion stimulus produced neural activity that ramped more slowly consistent with impaired quality of sensory evidence.

The neurons showed significant increase in how much evidence was accumulated before a decision, preventing a reduction in the overall accuracy, they said.

The findings were published in the journal Neuron.