Which of the following might serve as a secondary reinforcer?

A secondary reinforcer is a stimulus that has acquired its reinforcing properties through association with primary reinforcers, which satisfy basic biological needs. In this context, grades serve as a secondary reinforcer because they are not inherently rewarding on their own; rather, they represent the achievement and can lead to primary reinforcers such as praise, parental approval, or even opportunities for better education and job prospects.

Grades symbolize success and are connected to the more fundamental needs for acceptance and achievement. They motivate individuals to aim for higher performance since positive grades can lead to tangible benefits in life. This association with important primary reinforcers helps establish grades as valuable incentives in educational and personal development contexts.

In contrast, food is a primary reinforcer as it directly satisfies hunger; money serves as a secondary reinforcer that can buy primary and secondary reinforcers but may not be a first thought like grades in academic settings; and praise, while motivational, is often considered a secondary reinforcer itself because it typically involves social approval rather than fulfilling a basic need directly.