Asking someone what they think about other people reveals much about their own personality. The reason is that people tend to see more of their own qualities in others. The generous person sees others as generous and the selfish person sees others as selfish.
Dr Dustin Wood, the study's first author, said:
"A huge suite of negative personality traits are associated with viewing others negatively.The conclusions come from a series of three studies. In one people were asked to judge the positive and negative characteristics of three other people. The more positively they judged those people, the more happy, enthusiastic, capable and emotionally stable they turned out to be themselves.
The simple tendency to see people negatively indicates a greater likelihood of depression and various personality disorders."
People who judged others more positively also turned out to be more satisfied with their own lives. Set against this, those who judged others more negatively had higher levels of narcissism and antisocial behaviour. The researchers even returned to the same people a year later and found the results were the same. This suggests that what people's ratings of others say about themselves remains stable over time.
Personality disorders are often diagnosed at least partly by how people view others, the authors write:
"...although narcissists may perceive others as being uninteresting or worthless, this may not reflect how they see themselves.The study was published in the Journal of Personality and Social Psychology (Wood et al., 2010).
Similarly, individuals displaying behaviors typical of paranoid personality disorder may believe that others are malevolent and untrustworthy, even though they may not see themselves that way.
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Machiavellianism is usually measured in part by asking individuals the extent to which they perceive a lack of sincerity, integrity, or selflessness in others' actions, and narcissistic behavior is thought to be prompted in part by a belief that other people are inferior, uninteresting, and unworthy of attention."
Comment: Unfortunately, it's probably not as simple as the study predicts. Psychopaths are masters of deception who thrive in darkness. They might suss out the goal of the question and say what puts them in the best light. People with serious personality disorders cannot be counted on to have objective perceptions. There is also social programming to never say anything negative to contend with. Humans are much more complex than what can be revealed (or concealed) by a single question.