The reason, according to Simine Vazire, the researcher behind the study, is that the high value we place on these two traits makes us too emotionally invested to rate ourselves accurately. Instead, we lean towards self-enhancement…or self-diminishment.
Our friends, who are not as attached to the identities we create for ourselves, are able to see us more clearly.
The same rule goes for other traits we tend to think of as desirable, according to Vazire. For example, our level of physical attractiveness, or how interesting a person we are, is more realistically assessed by our friends (and research suggests that most of us see ourselves as less attractive and less interesting than we really are.)
Friends also tend to be right when they judge us on traits that can be easily spotted from our facial expressions or how we move, like how extraverted we are, says the research. But when it comes to interpreting body language, closeness isn’t even that important. Strangers can tell just as much as friends.
Are we privileged at all when it comes to knowing our own selves? According to the study, we’re generally better at judging traits that express themselves more internally than externally —our levels of happiness, anxiety and self-esteem, for example.
But, as you probably guessed, close friends are able to see even these more subtle aspects of our personality.