ABSTRACT
People not only know things, they know how to do things. The difference be tween these two types of knowledge-often termed declarative and procedural-is intuitively compelling. For example, people can often learn a fact after hearing it once. But it is less likely that someone can learn a skill from one-time instruc tion, without having an opportunity to engage in repeated, often laborious prac tice (Anderson, 1983).
