# A Negative Reputation Reduces Trust Despite Trustworthy Behavior

## TL;DR

People are less likely to trust someone with a bad reputation, even if they act kindly, and this is linked to brain activity.

## Contribution

First study showing negative reputations reduce trust despite good behavior and correlate with reduced theta brain activity.

## Key findings

- Negative reputations lead to fewer trust decisions, even when contradicted by cooperative behavior.
- Positive reputations maintain high trust when confirmed but decrease when contradicted.
- Negative reputations correlate with reduced fronto-lateral theta activity during trust decisions.

## Abstract

Interpersonal trust decisions are guided by reputation. However, it remains unclear how positive and negative prior reputations that are inconsistent with a partner's behavior are integrated at the behavioral and neural levels and how this informs daily trust decisions. In this two‐part study, 54 subjects first played an iterated 20‐trial Trust Game with four anonymous partners introduced as “cooperative” or “individualistic” while EEG was recorded. The partners’ behavior then either confirmed or contradicted this prior reputation. Subsequently, the subjects completed a three‐day ecological assessment measuring trust in daily interactions. According to the results, negative prior reputations were associated with fewer trust decisions, even after being contradicted by cooperative behavior. The frequency of trust decisions remained high if positive prior reputations were confirmed and decreased if they were contradicted. Trial‐by‐trial analyses showed that negative priors were still related to a lower trust choice probability, even if they were contradicted in the previous trial, paralleled by a decrease in fronto‐lateral theta. Mean trust levels across laboratory conditions were descriptively associated with mean trust levels in daily interactions. In sum, these findings indicate that a person with a negative prior reputation is less trusted, even if this person behaves in a positive way.

Our study is the first to demonstrate that negative prior reputations not only decrease trust likelihood despite contradictory evidence but also correlate with reduced fronto‐lateral theta activity. Thereby, it highlights the resistance to revising trust when reputational bias is negative. It is also the first to report data on the prediction of daily trust decisions by theta power differences during laboratory trust games.