What is the stimulus-response theory in psychology?

Overview

Ivan Pavlov (1849-1936) pioneered classical conditioning, the first form of stimulus-response theory. Pavlov was a Soviet researcher studying the digestive process through prolonged experiments with dogs. While doing this, Pavlov noticed that his dogs began salivating before they were brought food. Pavlov then conducted additional experiments to measure the amount of saliva produced by the dogs when they were prompted with various stimuli. He discovered that over time he could get the dogs to associate certain stimuli with certain responses. In his most famous experiment, Pavlov rang a bell before giving his dogs food. The dogs eventually salivated at the sound of the bell, regardless of whether or not Pavlov gave them food. The dogs had been conditioned to pair the stimulus of the bell with the response of salivation.

Several important terms have been derived from Pavlov's work. In this particular experiment, the food was an unconditioned (untaught or natural) stimulus and Pavlov's dogs' salivation was an unconditioned response. By pairing the unconditioned stimulus with a neutral stimulus (ringing the bell), the dogs came to associate the two. Thus, the neutral stimulus became a conditioned (taught) stimulus, and the dogs' salivation in response to it became a conditioned response. The conditioned response is usually the goal of this kind of experiment, which therapists often conduct with humans.

It is important to note that in classical conditioning, the unconditioned and conditioned responses targeted are always involuntary. This means that responses such as nausea, blinking, salivating, and increased heart rate are all acceptable. However, any voluntary response, such as putting on a seat belt, pacing a room, or flipping a switch falls under the category of operant conditioning.

Inspired by Pavlov's work, John B. Watson (1878-1958) was the first psychologist to intentionally apply classical conditioning to a person. Watson used a young child, referred to in his published work as "Little Albert," to prove that humans could be conditioned in the same way as Pavlov's dogs. Little Albert had no fear of small animals but cried whenever a steel bar was hit with a hammer, producing a loud noise. Little Albert was then allowed to play with a lab rat, which he seemed to enjoy. After some time, whenever Little Albert was presented with the lab rat, Watson hit the steel bar with the hammer. Eventually, Little Albert cried whenever he saw the lab rat. He even came to fear anything white or fuzzy that looked like the lab rat. While completely unethical by today's standards, this experiment was a milestone in behavioral therapy because it proved that fear is often a learned response and not something inherent in the individual.

Psychologist B.F. Skinner (1904-1990) first practiced operant conditioning and is best known for his creation of the "Skinner Box." He used the Skinner Box to teach lab rats various tasks. The box had an electric floor, a lever that dispensed a food pellet when pressed, and various lights and speakers. Using the box, Skinner was able to encourage different behaviors in the rats such as pulling the lever in response to stimuli.

Skinner divided his methods of behavioral modification into several categories. First, he used the concepts of reinforcement and punishment. In this context, reinforcement is anything that encourages a desired behavior, and punishment is anything that discourages a desired behavior. Second, he added the qualifiers "positive" and "negative," where positive indicates the addition of a stimulus, and negative indicates the removal of one. For example, suppose the desired behavior is to get the rat to pull the lever. Giving the rat a food pellet (a stimulus) when the lever is pulled is positive reinforcement. In this example, the food pellet is the stimulus and the action, pulling the lever, is reinforcement. If Skinner decided to shock the rat whenever it did not pull the lever, it would be negative reinforcement. The action is still reinforcement because pulling the lever is being encouraged, but it is negative because a stimulus (the shock) is being taken away when the rat performs the desired behavior.

This same process applies to punishment. With punishment, though, a stimulus is added to discourage a behavior. Suppose a parent spanks a child for misbehaving. Spanking is the stimulus. Because a stimulus is added, it is called positive punishment; whereas taking away a child's toys because he or she misbehaved is negative punishment.

Operant conditioning is often used to treat people with addictions. The families of individuals being treated for addiction are encouraged to reward them for making healthier choices and increasing the number of days abstinent. The reward must be substantial, however, to motivate the person to make this choice. The families must withdraw these rewards if the addicted individual makes unhealthy choices.

Psychologists use a similar technique to treat individuals with phobias. People with phobias have an irrational fear of an object. Because of this, they try to avoid the object whenever possible. With Systematic Desensitization (SD), psychologists seek to help patients overcome their phobia by gradually exposing them to the object, a type of positive reinforcement.

Tyler J. Biscontini

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Goldman, G. Jason. "What is Operant Conditioning? (And How Does it Explain Driving Dogs?)." Scientific American. Nature America, Inc. 13 Dec. 2012. Web. 21 Jul. 2014. <http://blogs.scientificamerican.com/thoughtful-animal/2012/12/13/what-is-operant-conditioning-and-how-does-it-explain-driving-dogs/>

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