Another effect that personality has on perception is the presumption that because a person is high or low in a certain trait, he or she must be high or low in other traits. For example, say that I introduce you to a friend of mine, Shoshanna. Within the first minute of interaction you perceive her as highly friendly. Based on your perception of her high friendliness, you’ll likely also presume that she is highly extraverted, simply because high friendliness and high extraversion intuitively seem to “go together.” If people you’ve known in the past who were highly friendly and extraverted also were highly open, you may go further, perceiving Shoshanna as highly open as well.

Your perception of Shoshanna was created using implicit personality theories, personal beliefs about different types of personalities and the ways in which traits cluster together (Bruner & Taguiri, 1954). When we meet people for the first time, we use implicit personality theories to perceive just a little about an individual’s personality and then presume a great deal more, making us feel that we know the person and helping to reduce uncertainty. At the same time, making presumptions about people’s personalities is risky. For example, if you presume that Shoshanna is high in openness, you might mistakenly presume she has certain political or cultural beliefs, leading you to say things to her that cut directly against her actual values.