One of the earliest psychological theories to be applied to schooling was behaviorism. According to this idea, humans learn by associating rewards with actions; we tend to continue to do (learn) that which is positively rewarded and avoid that which is negatively rewarded. The type of learning associated with behaviorism is called conditioning. Conditioning is the theory underlying many external motivations including grades and awards. Despite its wide use, researchers have found it does not explain human learning very well. Conditioning is useful when one is trying to establish habits in students, but the outcomes are unpredictable; what the teachers intend may not be the habit that results. Most experienced educators have abandoned conditioning as a tool for organizing their teaching.