Nonassociative learning occurs when an organism is repeatedly exposed to one type of stimulus. One important type of nonassociative learning is habituation. A habit is an action that is performed repeatedly until it becomes automatic, and habitutation follows a very similar process. Essentially, a person learns to “tune out” the stimulus. For example, suppose you live near an emergency room and ambulances pass by your house on a regular basis. When you first moved into the house, the sound of the sirens was annoying and loud, and it always made you cover your ears. However, after living in the house for a few months, you become used to the sound and stop covering your ears every time an ambulance wails. You may even become so accustomed to the sound that it becomes background noise and you don’t even notice it anymore.

Dehabituation occurs when the previously habituated stimulus is removed. More specifically, after a person has been habituations to a given stimulus, and the stimulus is removed, this leads to dishabituation; the person is no longer accustomed to the stimulus. If the stimulus is then presented again, the person will react to it as if it was a new stimulus, and is likely to respond even more strongly to is than before. In the ambulance example above, dishabituation could occur when you go away on a vacation for a few weeks to a quiet mountain retreat. The ambulance noise is no longer present, so you become dishabituated to the constant noise. When you return home and to the noisy ambulances, you are acutely aware of the wails of the ambulance sirens. The noise may cause you to cover your ears again or react more strongly because you have become dishabituated to the sound.