Counterconditioning and Desensitization
Debra F. Horwitz DVM, Diplomate ACVB
Counterconditioning and desensitization are the cornerstones to treatment of fears and anxieties. Yet the treatment of these conditions can be difficult. First, it is important to accurately identify the fearful or anxiety producing stimulus. Then, it is important to break the stimulus down into discrete units. Progress with treatment may be slow and animals may not generalize from the treatment sessions to real experiences. In order to be successful in modifying behavior in dogs and cats a good understanding of learning, reinforcers and punishers is necessary.
What is learning? Learning is the relationship between behavior and consequence, between making a response and the outcome of that behavior. The results obtained affect later behaviors by either increasing or decreasing the likelihood of future similar responses. What is important is to realize that behavior is something that occurs all the time. Therefore, when you remove a behavior from an animal's repertoire, it will be replaced with something else. The goal of behavior therapy is to structure that replacement behavior in the correct way.
Since behavior is the result of behavior-consequence relationships understanding how they function is helpful. Generally speaking there are four types of behavior-consequence relations. First, behavior can result in positive consequences. This is positive reinforcement and will produce an increase in the behavior that resulted in the positive event. Second, behavior can result in negative consequences. This is punishment, and should result in a decrease in the behavior that caused it. Third, the behavior can result in the removal of something unpleasant. This is negative reinforcement or escape and will increase the likelihood that the preceding behavior will occur again. Lastly, there are behaviors that result in the elimination of something pleasant, and this is called omission. 1 Learning occurs best when there is a clear relationship between the timing of the two events (behavior and consequence) and the predictiveness of the consequences.
Learning principles and behavior modification techniques
The previous discussion showed that behavior is controlled by its consequences-either pleasant ones or unpleasant ones.
Reinforcement is a positive relationship between behavior and outcome. The more you do, the more you get, and what you get is good. In other words, behavior will be repeated. There can be positive reinforcement, often called a reward. Positive reinforcement and rewards are often used synonymously, but that is not always true. It is easy to see a food treat or a pat on the head as a reward for the dog. However, it is often more difficult to determine why some behaviors still exist because the reward is not clear. For example, what it the reward for a dog when it barks at the mailperson? The reinforcement comes from the mailperson leaving, and therefore the dog will continue to bark. The dog has erroneously assumed that the barking behavior made the person leave, and therefore will engage in the behavior again.
Negative reinforcement is the removal of something unpleasant that increases the likelihood that a behavior will be repeated. In this situation there is a negative relationship between behavior and outcome. One way to look at this relationship is to realize the more an animal engages in the behavior, the less negative outcome is obtained. The easiest example of negative reinforcement to understand is escape behavior. If an animal is anticipating an aversive outcome, perhaps a reprimand from the owner, if the animal can escape, or not be caught, then the aversive outcome will not occur.
Punishment is a situation where there is a positive relationship between behavior and outcome, but the outcome is negative. In other words, the more of a behavior an animal does, the more of a negative outcome is obtained. This is a situation that should make behavior decrease. This is an extremely important component of punishment. When punishment is used to change behavior, there should be a decrease in the target behavior in very few applications of the aversive event. If not, then either the punishment is not being appropriately applied, or applied to the incorrect behavior. Punishment also has the possibility of causing anxiety, fear and aggression and is not the recommended means of changing behavior.
Schedule of reinforcement
The way the both reinforcement and punishment are used can greatly influence their effectiveness. This is often termed the "schedule of reinforcement". How behaviors are rewarded can be powerful determinants of future behavior. Schedules of reinforcement can be based either on time (intervals) or amount of work, or number of responses (ratio). Schedules can be fixed, meaning that after so much time or a set number of responses reinforcement is given. Alternatively, behavior can be reinforced on a variable schedule, meaning that a period of time or a number of responses must take place, but that period varies from reinforcer to reinforcer, with an average time or number of responses. Reinforcement given on a variable schedule results in strong acquisition of the response. This means that the rewards are given intermittently, and the animal is not exactly sure when the reinforcement or the punishment will occur. The outcome also must be closely associated in time with the behavior for best results.
Extinction is a procedure used to end a behavior. Extinction occurs when behavior is no longer reinforced. When this occurs, eventually the behavior will stop. However, it is very common, especially if the behavior has been maintained on a variable ratio of reinforcement, for the behavior to temporarily increase and this is called an extinction burst. When trying to get a behavior to extinguish it is extremely important to identify ALL reinforcers and eliminate them.
Habituation is a process by which a stimulus no longer evokes a response. Usually this occurs with repeated presentation of a stimulus and the animal learning that it does not signal anything important.
Flooding is used to treat fears of harmless stimuli by forcing the animal to stay in the presence of the stimuli until the fear is extinguished.
Classical conditioning is the pairing of an unconditioned stimulus, with a neutral stimulus that results in a conditioned stimulus and a conditioned response. Classical conditioning can occur in both positive and negative ways. The timing of the presentation of the stimulus, the saliency of the stimulus and the predictability of the stimulus and the reinforcement influence the conditioning process.
Conditioned emotional response refers to establishing fears through a classical conditioning paradigm. This entails the association of a fear-producing stimulus with a previously neutral object. This type of learning can be very powerful and hard to extinguish.
Operant conditioning is learning how ones actions result in consequences; i.e. the individual causes the results. This is a stimulus-response/response-consequence relationship. In other words, what the animal does is critical to what happens next and those results dictate if the behavior will occur again. Behavior becomes more likely if it is reinforced, less likely if it is punished.
Counterconditioning is teaching a behavior that is incompatible with the previous response. An example is to teach a dog to sit and stay instead of lunging. What is wanted is that the response be behaviorally and physiologically different from the previous response. Therefore, facial expressions, body postures, respiratory rate etc. are all-important components in the response. The goal is to change the association with the stimulus. Classical counterconditioning occurs when you pair a previous stimulus with some unconditioned response such as food.
Systematic Desensitization is gradually exposing an animal to stimuli at a low level so as not to evoke an undesirable response and conditioning relaxation responses instead. Paired with counterconditioning, this allows animals to learn to behavior properly to stimuli that caused fear, aggression or other problem behaviors. The stimuli must be presented on a gradient from low to high without evoking the inappropriate or unwanted response. Therefore, the arrangement of the stimuli becomes very important.
Obstacles to treatment success in counterconditioning and desensitization (CCDS)
Generally there are five obstacles to treatment success. First is stimulus discrimination, the ability of the animal to distinguish the stimulus. In addition, the stimuli presented must be relevant and control the behavior or the animal does not learn the appropriate response. Then the animal must learn what to do in the presence of the stimulus. Second, transfer of learning must take place for CCDS to work. The animal must learn to pay attention to the relevant stimulus and ignore irrelevant stimuli. Third, the animal must learn to generalize from the learning situation to the real world. This requires the behaviorist to know what stimuli are controlling the response. Fourth, inappropriate rewards may allow the animal to discriminate improperly and learn a different stimulus-response relationship than what was intended. Finally, the animal can be come more sensitive rather than less sensitive to the stimulus.
To overcome these obstacles, accurate history taking, good observational skills and appropriately set up treatment plans are important. The behaviorist and the owner must be willing to proceed slowly and set up the animal to succeed. Finally, the animal must be exposed to a variety of stimuli once the behavior is learned.
Changing behavior takes a good history, a realistic treatment plan and good supervision and cooperation between behaviorist and pet owner as well as a complete understanding of learning and behavior modification techniques.
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