Learning may be defined as a relatively permanent change in behaviour that occurs as the result of experience. Not all changes can be explained as learning, so our definition has to be qualified to exclude them. The phrase relatively permanent excludes changes in behaviour that result from temporary transient conditions such as fatigue or the influence of drugs.
By specifying that learning is of experience we exclude changes that are due to maturation, disease, or physical damage, could be defined more simply as profiting from experience, were it not that some learning snot “profit” the learner: useless and harmful habituate learned just as are useful ones.