What do water, food and drugs have in common?
Reinforcers can be classified as either primary or secondary. Reinforcers, which are learned, are called (secondary) as for example, money, getting good grades, etc. Reinforcers, which do not have to be learned, are called (primary). What does a glass of water, a meal, a cup of coffee, an aspirin, a cigarette, or an ounce of alcohol have in common? Guess what? They may all be classified as primary reinforcers and as drugs! 
Check out an online dictionary for a definition of drug such as the following hyperlink. http://medical-dictionary.com/
The classic definition of a drug, found in almost every introductory book to pharmacology,
classifies a drug as 'any chemical substance that affects living protoplasm."
Don't be too self-righteous when you classify others as drug takers and yourself as
non-drug takers. A word of warning might be that the word drug is something that has been
arbitrarily defined by certain segments of society and has lost most of its meaning.
For example, eating at the same time every day would be termed as a fixed schedule. Eating the same amount every day would be labeled a ratio schedule. If one eats at a different time each day it would be an interval schedule. If one eats a different amount each day it would be a variable ratio. If one eats a different amount each day at a different time, it would be a variable ratio-interval schedule.[4 ]
What type of schedule do you think is usually the strongest type of reinforcement schedule?
Be careful here as the schedule that you might think is the strongest may actually be the weakest. You can only tell how strong a reinforcement schedule is when you take away the reinforcement schedule and then notice how long t before the behavioral is extinguished
Give an example and provide your reasoning. Reasoning here is intended to mean that you must explain how you drew your conclusions from the premises, or the arguments, you used. Which is likely the least type of reinforcement schedule? Give an example and explain your reasoning. How is becoming aware of the reinforcements and the reinforcement schedules important in reducing the impact of stress on your life?
1. Eric Goode, Drugs in American Society, New York: Alfred Knopf, Inc., 1972, p. 18
2. http://www.msnbc.com/news/526132.asp The Brain-The Origin of Dependence, Newsweek, February 2001