Final answer:
The term 'reinforces behavior after varying and unpredictable number of responses' defines a variable ratio reinforcement schedule, a concept in Psychology used within behaviorism to describe a powerful method of reinforcing desired behaviors at unpredictable intervals, resulting in high and consistent levels of these behaviors.
Step-by-step explanation:
The phrase reinforces behavior after varying and unpredictable number of responses refers to the variable ratio reinforcement schedule in the context of Psychology, particularly within the field of behaviorism or learning theory. This schedule of reinforcement is part of what is known as partial reinforcement, where the desired behavior is not reinforced every time it is performed. Instead, in a variable ratio schedule, the reinforcement is provided after an unpredictable number of responses, making this schedule very powerful in maintaining high and consistent levels of desired behaviors without extinction.
An example of the variable ratio schedule can be seen in gambling, where a player receives a payout after an unpredictable number of plays. This unpredictability keeps the behavior steady and persistent, as the individual never knows exactly when the reinforcement will come, but knows it is possible with each response. This contrasts with fixed ratio schedules, where reinforcement occurs after a predictable number of responses, and can cause a brief pause after the reinforcement as the subject anticipates the next set number of responses required for the next reward.