In the first phase of an experiment, food is given to a dog…

In the first phase of an experiment, food is given to a dog and it salivates. In the second phase, a light is turned on, the food is given, and the dog salivates. After several pairings, every time the light is turned on, the dog salivates. After continual pairings with the light, the salivation begins to decrease. This is called ______.