Cognition is a “-tion” noun like digestion, per ception, and motivation. It does not refer to some fixed entity but to a set of processes and capaci ties necessary for the acquisition and manifesta tion of knowledge. It is derived from the Latin cognoscere (to know). Knowing involves pro cesses and capacities that can be identified from behavior. All too often, such processes are reified; it would be better to avoid the noun and to re fer to cognitive processes or aspects of behavior, or even to describe the behaviors of interest as cognitive, just as behavior can be described as adaptive or intelligent or persistent.