Learning involves acquiring or modifying knowledge, behaviors, skills, or preferences through experience. It is defined as a relatively permanent change in behavior resulting from practice or experience. Key aspects of learning include it being a change in behavior, occurring through experience over time, and the changes generally being permanent. Learning allows organisms to adapt to their changing environments. It is a purposeful, goal-oriented process that is both individual and social in nature. The rate of learning is not uniform and much occurs initially, with a plateau stage sometimes occurring where no additional learning takes place.