Behavior analysis focuses on the principles that explain how learning takes place. Positive reinforcement is one such principle. When a behavior is followed by some sort of reward, the behavior is more likely to be repeated. Through decades of research, the field of behavior analysis has developed many techniques for increasing useful behaviors and reducing those that may cause harm or interfere with learning.

Applied behavior analysis (ABA) is the use of these techniques and principles to bring about meaningful and positive change in behavior.

As mentioned, behavior analysts began working with young children with autism and related disorders in the 1960s. Early techniques often involved adults directing most of the instruction. Some allowed the child to take the lead. Since that time, a wide variety of ABA techniques have been developed for building useful skills in learners with autism from toddlers through adulthood.

These techniques can be used in structured situations such as a classroom lesson as well as in "everyday" situations such as family dinnertime or the neighborhood playground. Some ABA therapy sessions involve one-on-one interaction between the behavior analyst and the participant. Group instruction can likewise prove useful.