Final answer:
The statement is true; the Premack principle is ineffective if the reinforcing activity cannot be managed, as this method relies on using a preferred activity to reinforce a less preferred one.
Step-by-step explanation:
It is true that if access to reinforcement cannot be managed, then the Premack principle, sometimes referred to as the Premack contingency option, is not a good replacement behavior. The Premack principle proposes using a more probable or preferred activity to reinforce a less probable or less preferred activity. For example, if a child prefers playing video games over doing homework, a parent might allow the child to play video games only after their homework has been completed.
In situations where the preferred activity cannot be guaranteed or controlled as a reinforcer, the efficacy of using the Premack principle as a replacement behavior reduces. The principle relies on the ability to consistently reinforce the less preferred behavior with the more preferred one. In conditioning processes, similar to the example of the toddler learning not to take toys due to time-out consequences, the contingent access to a reinforcing activity is necessary for the behavior change to hold.