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OpenPSYC is a free online resource for students in Introduction to Psychology courses. Use the links on the right to learn more about the site, visit a course module or search by keyword.

Unlearning Associations

Imagine that an animal or human has an undesired response to a stimulus.  For example:
  • Every time the dog hears the fire alarm he barks aggressively
  • Clients have extreme fears (phobias) that disrupt their lives, like spiders, clowns or heights
  • A friend is trying to quit smoking cigarettes but every time she sees one she craves it
There are a number of strategies we can use to reduce, and eventually eliminate, the relationship between a stimulus and a response.


Habituation is simply getting used to something.  We habituate to things all the time - you walk into a room and notice that the air conditioning vents are making a loud humming noise.  At first the sounds is very obvious to you, but after a while you stop noticing it because you have habituated.  If you've ever started wearing a piece of jewelry, or a hat, you probably noticed that the first few days you really felt it, and after a while you just got used to it and didn't notice anymore.

The first time the dog hears the fire alarm it might react with fear or aggression, but if we kept playing the sound for hours the dog's response would slowly start to fade… in this case, the dog is essentially learning that nothing happens - the stimulus takes on less and less meaning over time.  So, one way to eliminate a response is to present the stimuli constantly.  When we try to use habituation to weaken an undesired response we call it flooding.  Now, before you decide to fix your friend's fears with this technique please understand that it is not always the best way to go - please consult with a professional!

Watch: Part 5 Primal Fears - BBC Explorations (http://youtu.be/fiy0rWAAkhA?t=2m2s)

Systematic Desensitization

A more gentle (and in some cases, more humane) way of addressing an undesired association is to start out with an easy stimulus and slowly work our way up to the real one.  Let's look at how this approach might be used to treat a phobia.  Note that we are simply presenting stimuli - if the client has no response (remains calm) then we can move forward to the next stimulus.

First, take a look at what it really means to have a phobia...

Watch: Lady is scared to death of Clowns – Coulrophobia (http://youtu.be/1h3Dh5QAD7w)

Now take a look at how we might treat a fear of nights using virtual reality to systematically desensitize the client.

Watch: Virtual reality therapy (http://youtu.be/CQgKEp_NhHk)


What if every time you saw a spider someone gave you $100?  With counter-conditioning the goal is to replace the undesired response by replacing the association.  If we want to reduce a fear response we might try to associate the stimulus with something positive.  On the other hand, we might also try to create a negative association with things we do not want to like as much (an aversive stimulus).

Let's see how counter-conditioning can be used to reduce an undesired response:

WatchPit Bull vs. Vacuum Cleaner | Counter-Conditioning Dog Training (http://youtu.be/WfgVXPmeOdo)

When we try to counter-condition away a positive response with an aversive stimulus this is called Aversion Therapy.  This is a bit of a controversial concept - and in the past it has been used to try and cure addictions, treat child sex offenders and, sadly, even to try and convert homosexuals into heterosexuals.  Regardless of the application, it is still helpful to understand conceptually how we can apply counter-conditioning to reduce a positive response.

If you have seen the movie Dodgeball you have seen Ben Stiller's character (White Goodman) try to reduce his craving for a donut using electrical shocks:

Watch: Dodgeball Donut Scene (http://youtu.be/l9AvVu-P6Do)