Food is considered a primary reinforcer, whereas is a secondary reinforcer.

Secondary reinforcers are learned or conditioned.  An example of a secondary reinforcer is grades or money.  Secondary reinforcers are learned and are reinforced by the continual use of the reinforcer.   Primary reinforcers are biological and include food, drink, and pleasurable activities.  

The three sociological perspectives include the beginner’s mind, culture shock, and the sociological imagination