Taking extra time to reflect on a past mistake before moving on doesn’t seem to help or harm future accuracy, according to a new study at New York University (NYU).
The researchers found that after we make a mistake, the brain tends to slow down in an effort to gather new information to prevent repeating the error, but at the same time, the brain tends to reduce the quality of evidence. These two processes essentially cancel each other out, say the researchers.
“Our research reveals that a combination of changes in the brain slow us down after mistakes,” explains Braden Purcell, an NYU post-doctoral fellow and a co-author of the study, which appears in the journal Neuron. “One gathers more information for the decision to prevent repeating the same mistake again. A second change reduces the quality of evidence we obtain, which decreases the likelihood we will make an accurate choice.”
Their findings, which address a long-standing debate on the value of deliberation after errors in decision-making, also potentially offer insights into mental health conditions that impair judgment, such as Alzheimer’s Disease and Attention Deficit Hyperactivity Disorder (ADHD).
“In the end, these two processes cancel each other out, meaning that the deliberative approach we take to avoid repeating a mistake neither enhances nor diminishes the likelihood we’ll repeat it,” says Roozbeh Kiani, an assistant professor in NYU’s Center for Neural Science and the study’s other co-author.
It’s been long established that humans often slow down after mistakes, a phenomenon called post-error slowing (PES). Less clear, however, are the neurological processes that occur under PES.
The NYU researchers sought to address this question through 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 researchers controlled the difficulty of each decision with the proportion of dots that moved together in a single direction. For example, a large number of dots moving to the right provided very strong evidence for a rightward choice, but a small number provided only weak evidence.
Humans and monkeys showed strikingly similar behavior. After making a mistake, both slowed down the decision-making process, but the pattern of slowing depended on the difficulty of the decision. Slowing was maximum for more difficult decisions, suggesting longer accumulation of information. The overall accuracy of their choices did not change, however, suggesting that the quality of accumulated sensory information was lower.
“Patients with ADHD or schizophrenia often do not slow down after errors and this has been interpreted as an impaired ability to monitor one’s own behavior,” explains Purcell.
“Our results suggest that this absence of slowing may reflect much more fundamental changes in the underlying decision making brain networks. By better understanding the neural mechanisms at work after we make a mistake, we can begin to see how these afflictions impair this process.”