A research team led by Professor Hitoshi Yamamoto of Rissho University experimentally examined how people evaluate others when the public reputation of the person involved in an interaction conflicts with their own personal experience with that person. The study was published in the international journal Evolution and Human Behavior on September 14, 2026.
In human societies, people often rely on reputation when deciding whom to help or cooperate with. This reputation-based mechanism for supporting cooperation is known as indirect reciprocity. The present study examined how people's judgments change when reputational information is combined with their own direct experience.
The researchers conducted two scenario-based experiments with participants in Japan, using situations involving coworkers at a restaurant and neighbors in a community. Participants were shown a situation in which one person either cooperated with or refused a request from another person. The researchers varied both the reputation of the person making the request and whether that person had previously cooperated with or refused to cooperate with the participant, and then examined how participants evaluated the person who responded to the request.
The results showed that when someone refused to cooperate with another person, evaluations of that refusal varied depending on the participant's prior experience with the person who refused. For example, even when that person had a bad public reputation, refusal was evaluated more negatively if the person had previously helped the participant. Conversely, even when the person had a good reputation, refusal was evaluated more positively if that person had previously refused to help the participant. In other words, when reputation and personal experience conflicted, personal experience was strongly reflected in evaluations of non-cooperation.
By contrast, cooperative behavior was generally evaluated positively regardless of the other person's reputation or the participant's own experience with them. This suggests that people do not evaluate cooperation and non-cooperation in the same way: when judging non-cooperation in particular, they place greater weight on how the person on the receiving end had previously treated them.
The study also found that even when the person being refused had a bad reputation and had previously refused to cooperate with the participant—a situation in which there appeared to be good reason not to cooperate—the refusal itself was evaluated neutrally rather than positively. This suggests that even when there is a reason to refuse cooperation, people do not necessarily regard such behavior as positively "good."
Previous research on indirect reciprocity, in which people use reputation to decide whom to cooperate with, has focused mainly on socially shared reputational information. In everyday relationships, however, public reputation and personal experience do not always match: someone may be well regarded by others but have treated us poorly, or may have a bad reputation despite having helped us personally. This study shows how people combine these two sources of information when evaluating others.
Professor Yamamoto commented:
"In everyday life, we judge others by combining many different kinds of information, including what we hear about them from others and what we have experienced ourselves. Our study provides one clue to understanding how people make judgments when these sources of information do not agree. In future research, we would like to examine how people use reputational information in environments where direct personal experience is limited, such as online rating systems and AI-mediated judgments."
