We present the rats with new things that might trigger their reflexive, or automatic, fear response, which is to freeze and sit still. When rats are exposed to a trigger such as a loud noise repeatedly and nothing bad happens, the reflex lessens. This is called habituation. The rats become more courageous, and they also learn that people are their friends. Then we do reward training. We give the animal something positive, like a treat, and pair it with the sound of a click. The rat learns that the click means food is coming.
The next step is called shaping, when we use the click to tell the rat it has done something we want. We start with a behavior that a rat naturally does and reward it as it gets closer to the behavior that we want. For example, a rat might naturally use its paws to investigate a small ball that we attach to its harness. We click and reward the rat. Through shaping we can gradually train the rat to pull on the ball to activate a switch when it is near a person.