Habituation – when one stops reacting to a meaningless stimuli. One is able to sense the stimulus and respond, but has learned not to. There is short term and long term habituation.
Short Term Habituation – stimulus eliciting the orienting response (or thing that makes you react) happens over and over again intensely in short intervals. The dog stops reacting relatively quickly within this period, but if the orienting response happens again after a break, there will likely be spontaneous recovery and there will again be a response.
Our friend's dog Pepper is terrified of children. Unfortunately (for her) Bug adores her. She sees Bug for about 4 hours two to three times a month. By the end of a visit she is calmer around Bug, but reverts to her fearful self the next time they meet.
Bug does not like the sensation of goats licking her. She loves to visit goats and feed them, but as soon as they lick her she squeals and tries to get away. By the end of the visit she allows the goats to lick her, but as soon as they try it the next time she squeals again.
Long Term Habituation – the stimulus eliciting the orienting response happens less frequently and with longer intervals between. These long intervals encourages long term habituation and as a result, there is less spontaneous recovery.
When we crate trained Havana to be alone at our house, the disappearance of a human brought out her orienting response (a puppy “hey! Don't leave me alone!). We made a point of leaving her crated alone one or two times a day and sometimes skipped a day here and there. (The advantages of working from home.) Over time her response to being alone was reduced and now she has no orienting response at all when she is alone in her crate.
There is a play room at the gym I use. Bug is perfectly safe there and has a pretty good time when she settles in, but she had a fit when I leave. My disappearance creates an orienting response of screaming as if she's being dismembered. My gym attendance isn't very regular, but as we've followed this same routine, Bug's response to my leaving gets less loud and of shorter duration. Maybe by the time she's 12 she'll be fine with me leaving.
Sensitization – the opposite of habituation. This happens when the reaction to an orienting stimulus gets stronger instead of weaker. It is usually involved in strong emotional responses and is more general than habituation.
Havana used to have no opinion about squirrels. However, she has been seeing more and more of them and has become very frustrated with her inability to chase them. Now when she sees squirrels she barks like crazy. (Even crazier than usual for a collie.)
Bug was watching a movie about a lost puppy. During a sad scene a sad song was playing and the music caused an orientating response. At first Bug didn't respond, but the more she listened to the song, the more upset she got. When there was a reprise of the song at the end of the movie she began wailing and could not settle down for the next 15 minutes.
Adaptation – does not involve learning. One stops reacting because of physical fatigue.
While there are examples of my own dogs going through this, what most quickly comes to mind is Cesar Milan. He will take a dog aggressive dog and run it on a treadmill until it is exhausted and then bring in another dog. The aggressive dog will not react because he physically cannot. He hasn't learned to ignore the other dog or to do a behavior incompatible to lunging or biting, just simply can't get up the energy to be aggressive. As soon as he's rested he will most likely respond aggressively again.
Before we got on the plane to visit family in Florida, Bug and I ran up and down an empty corridor in the airport. When we got on the plane she was (relatively) quiet. She didn't learn that she was supposed to be quiet on the plane, she was just too tired to bounce and be noisy. We didn't have time to run before our connecting flight and she proved that she hadn't learned to be quiet on a plane.
Learned Irrelevance – one stops responding to a stimulus because there is no consequence in the presence of the stimulus. Unlike habituation, it is unlikely to have spontaneous recovery. Instead it actually makes it more difficult for the student to condition to the stimulus because it has been irrelevant for so long.
I introduced the word “heel” to Cousteau long before he ever understood what it meant. As a result he didn't really have a heel. When I tried to teach him heel position he had a very difficult time putting together the word “heel” and where he was supposed to walk because for so long heel just sort of meant I was going to walk away and he'd better come with me eventually.
Bug used to ask to go to bed. Now when we say “one minute to bed time” and then “bedtime” she has a fit. We've gotten into the bad habit of saying these things and then not following through with putting her to bed because it's such a pain. When we do pick her up for bed she has a fit because it's completely caught her off guard. The transitional minute and the phrase “bedtime” have no mean for her any more. (Way to go, Momma and Daddy! :P )