Examples of primary reinforcers, which are sources of psychological reinforcement that occur naturally, are food, air, sleep, water and sex. These reinforcers do not require any learning process in order to be effective; therefore, they are considered unconditional.
Primary reinforcers are generally a result of the evolutionary process, and experience and genetics both impact the success of each reinforcer. The effectiveness of each primary reinforcer, therefore, differs among individuals.
Primary reinforcers play a key role in the operant conditioning process in psychology, which is used to achieve a desired behavioral result by using various types of reinforcement. They are used in combination with secondary reinforcers, which use stimuli to reinforce the desired behavior.