What is defined as anything that increases the likelihood of a behavior being repeated?

The term that is defined as anything that increases the likelihood of a behavior being repeated is "reinforcer." In the context of behavioral psychology, a reinforcer is a stimulus or event that follows a behavior, making it more probable that the behavior will occur again in the future. This concept stems from operant conditioning, where behaviors are shaped by consequences. When a behavior is followed by a positive consequence, such as praise or rewards, it strengthens the likelihood that the behavior will be repeated.

Reinforcers can be categorized into positive reinforcers, which add a desirable stimulus after a behavior, and negative reinforcers, which involve the removal of an aversive stimulus to increase the occurrence of a behavior. Essentially, any object, event, or condition that encourages a behavior to be repeated fits within the definition of a reinforcer.