Answer:
A secondary reinforcer.
Explanation:
Operant conditioning can be defined as an associative learning process which involves reinforcing the strength of a behavior. Thus, the outcome depends on the response in operant conditioning.
A reinforcement of a desired behavior involves the process of strengthening a positive behavior being exhibited by an individual through the use of stimulus. Therefore, making the behavior to be exhibited in the future by the individual.
Basically, by reinforcing desired behaviors with rewards, parents, teachers and leaders can help people in building positive norms.
In this scenario, when a child behaves well for an entire day, the child earns a star. After acquiring fifteen stars, the child is allowed to pick a prize from a toy chest. The star is best described as a secondary reinforcer because it motivates or influences the decision of the child to behave well for an entire day.