Reduced judgment updating to concurrent social feedback in abstinent individuals with methamphetamine use disorder

Human beings are wired to look to others for clues about how to see the world. When we are unsure whether a stranger is trustworthy, or if a new idea is safe, we often glance at the opinions of our friends or the general public to adjust our own views. This process, known as social influence, helps us navigate complex environments and is a cornerstone of how we learn and adapt. However, for people struggling with addiction, the brain's ability to process these social signals can become disrupted. Methamphetamine use disorder, a condition marked by compulsive drug use despite severe consequences, is known to damage the brain's decision-making centers. While scientists have long studied how addiction affects memory and impulse control, a deeper question remains: how does the disorder change the way a person updates their own opinions when faced with conflicting advice from different social groups? Specifically, if a person is told one thing by a friend and something else by society at large, how do they weigh these competing voices to change their mind?

A team of researchers set out to answer this question by observing how individuals who have stopped using methamphetamine handle social feedback. They recruited thirty-eight people who had been abstinent from the drug for an average of nearly seventeen months and compared them to forty-nine healthy individuals with no history of drug use. The participants were asked to perform a simple task: look at a series of faces and rate how attractive they found each one on a scale from one to ten. After giving their initial rating, the participants saw two new numbers. One number was labeled as a "peer rating," supposedly coming from friends in the room, and the other was labeled as a "societal rating," supposedly coming from a large group of people in the general public. In reality, these numbers were generated by a computer program and were not real opinions from other people. The participants then had to give a final rating for the face. The researchers watched closely to see how much the participants changed their minds based on the gap between their original rating and these two new sources of information.

The results revealed a distinct difference in how the two groups processed this information. When the computer feedback suggested a different opinion than the participant's initial thought, the healthy control group adjusted their final rating to move closer to the feedback. They showed a healthy sensitivity to both the peer and the societal cues, shifting their judgment when the information warranted it. In contrast, the individuals with a history of methamphetamine use disorder were significantly less likely to change their minds. Even when the feedback came from a peer, which might typically carry more weight, or from society at large, their ratings remained stubbornly close to their original guess. The data showed that the abstinent group was less sensitive to the peer feedback by a measurable margin, and they were also less responsive to the societal feedback, though the difference was slightly smaller for the latter. Essentially, when faced with two different social voices telling them to reconsider, the people in recovery held onto their initial judgments more tightly than the healthy participants did.

To understand how these two sources of information were being combined, the researchers used a method of testing different mathematical descriptions of the decision-making process. They compared a model where the brain treats peer and societal feedback as separate, independent signals against a model where the brain simply averages the two sources together as one single piece of advice. The analysis showed that for most participants, both in the control group and the recovery group, the equal-weight composite model provided the best statistical description within the tested set. However, the researchers explicitly noted that this preference did not identify a unique psychological representation or prove that the brain actually pools these sources together; the models were overlapping descriptions rather than mutually exclusive mechanisms. The key finding was not in the complexity of the model, but in the strength of the signal. The "weight" given to this combined social feedback was much lower in the group with a history of methamphetamine use. It was as if the volume of the social voice was turned down for them, making the external opinions feel less urgent or credible than they did for the healthy controls.

The study also looked at specific scenarios where the peer and societal feedback disagreed with each other, such as when a friend said a face was very attractive but society said it was not. In these moments of conflict, the healthy participants showed a clear ability to shift their ratings based on the specific source of the disagreement. The group in recovery, however, showed a reduced ability to navigate these conflicts in some instances, though the researchers noted that specific contrasts were not always statistically significant; for example, the difference between groups was not significant when societal feedback was the dominant conflicting source. The researchers noted that this reduced updating did not necessarily mean the participants were ignoring the information entirely, but rather that their brains were not integrating it as effectively to change their existing views. The study did not find that one group was "better" at the task in an absolute sense, since there is no objectively correct rating for a face, but it did show a clear difference in the flexibility of their social learning.

These findings offer a new window into the social challenges faced by people recovering from addiction. The results suggest that the difficulty in updating judgments is not limited to a single type of social input but extends across different sources of influence. While the study cannot prove that the drug use caused this specific change in brain function, nor can it say whether this trait existed before the addiction began, it clearly identifies a pattern of reduced responsiveness to social feedback in a controlled setting. The researchers caution that this does not mean people in recovery are incapable of social connection or that they cannot learn from others in real life. Instead, it highlights a specific, measurable difference in how their brains process conflicting social information during a moment of decision. Understanding this mechanism is a step toward recognizing that recovery involves not just stopping drug use, but potentially relearning how to trust and integrate the social world around them.