In this article, we propose a comprehensive conception of what personality traits are and what they mean in lay personology. Our conception is a pragmatic one that relies on the ecological concept of affordance and the theory of dual knowledge. It is not based on the same knowledge-building process as other pragmatic conceptions in that it distinguishes evaluative knowledge, produced by the generalization of affordances, from descriptive knowledge, deemed to be of limited importance in trait usage. It posits that an essential component of the meaning of traits is how others act: towards the persons who possess these traits. We present a compilation of ten experimental studies in various areas of interest (statistical studies of trait/behavior associations, semantic decision-making, person memory, judgments at zero acquaintance) to prove the importance of the evaluative component composed of others' behaviors (OBs). These experiments show that the evaluative component 1. includes a repertoire of behaviors that is just as reliable for encoding traits as the repertoire of behaviors ascribed to the target; 2. can be just as accessible as the descriptive component for highly evaluative traits; 3. is very powerful in structuring mental representations of persons; 4. is mon highly activated in social contexts, especially in work-evaluation situations, and 5. is more discriminative than the descriptive component in immediate appraisals of persons.
