1) Roughly, acquisition, or the process by which behavior is added to an organism's repertoire; a relatively permanent change in behavior. The term has been used in so many different ways in both technical and colloquial vocabularies that it may be of limitted usefulness. The decision about whether learning has occurred and what has been learned sometimes depends on what the experimenter looks at. Latent learning provides an example. A rat explores a maze, and the results of this exploration are assessed later when food reinforcers are available at the end of the rat's run through the maze. Latent learning is said to have occurred if the rat then negotiates the maze more rapidly and/or accurately than if it had not explored. The difficulty is that exploring the maze involves other contingencies (e.g., which turns lead where); these contingencies act on behavior but their effects are harder to get at than those involving the food reinforcers.

2) The relatively enduring changes in behavior that result from conditioning processes.

3) Any enduring change in behavior produced as a function of the interaction between the behavior and the environment. Often used to describe motor or cognitive skills, but term also may refer to social, affective, personal, and other classes of behavior.

4) The change in behavior from living and behaving in any environment.