Secondary reinforcers refer to stimuli which become rewarding when paired with other reinforcing stimuli. These reinforcers aren’t important for survival like the primary reinforcers, but are still vital for daily living. These reinforcers are also known as Conditioned Reinforcers. For example: money, grades and praise are conditioned reinforcers.
In other words, secondary reinforcement is the process in which certain stimuli are paired with primary reinforcers or stimuli in order to strengthen certain behaviors. It’s a must that a reinforcer be paired with a strong primary reinforcer in order to turn it into a secondary reinforcer itself.
Dog trainers often use sound of a whistle paired with treats to strengthen certain behavior in the dog. After a certain time, the dog automatically starts to react to the sound of the whistle. The sound of the whistle thus starts working as a secondary reinforcer.
A teacher grants her students tokens every time they complete their assignments in time or follow classroom rules. Then at the end of the week she collects the tokens off of each student and in exchange distributes equal number of chocolates. Because of this, the students work harder and harder to receive the tokens, knowing that they will be rewarded with treats at the end of the week.
Here, the tokens are used as reinforcers to shape positive behaviors of the students. The treats she chooses to pair with the tokens act as Primary reinforcers.