Which of the following describes an establishing operation (EO)?

An establishing operation (EO) is a variable that increases the effectiveness of a stimulus as a reinforcer. This means that certain conditions can alter how valuable a particular reward is at a given time. For instance, if an individual is hungry, food becomes a more powerful reinforcer because the state of hunger increases the desirability and influence of food as a motivator for behavior.

In this context, EOs can influence behavior by enhancing the value of potential reinforcers, thereby encouraging behaviors that lead to those reinforcers being attained. Recognizing EOs is crucial in behavioral psychology since they help to explain why individuals might engage in certain behaviors under specific circumstances.

The other options illustrate different concepts but do not accurately define an establishing operation. Some describe factors that either decrease or maintain reinforcement effectiveness, while others concern the removal of aversive stimuli, which pertains more to operations that decrease behavior (such as abolishing operations) rather than establishing operations that enhance the appeal of a reinforcer.