Obviously there was something about the door that was different from the other doors. So she painted the doors very carefully, arranging the textures on the faces of the doors exactly the same. Still the rats could tell. Then she thought maybe the rats were smelling the food, so she used chemicals to change the smell after each run. Still the rats could tell. Then she realized the rats might be able to tell by seeing the lights and the arrangement in the laboratory like any commonsense person. So she covered the corridor, and still the rats could tell.

While she kept trying different things, Feynman imagined he was a rat and walked around the room passing the office door several times. Each time he noticed a different sound. Then suddenly he had the answer. He suggested that one of the conditions rats relied on to return to a food source was sound. They could tell by the way the floor sounded when they ran over it. To prove it, he covered the corridor in sand and finally was able to fool the rats. He discovered, by imagining he was a mouse, what the rats were really using to find food-not what the experimenter assumed they were using.

Try to imagine yourself as the subject or some part of the subject and try to see the situation from its perspective.  Imagine that you are trying to design a new clock. Ask yourself what it would be like to be the minute hand on a clock. Can you imagine yourself to be a unit of time? How would an hour feel? A minute? A second? What would it say to me if our positions were reversed? What would it say to me if it could think and talk the way I can? Identify with an object or process and try to see the problem from the perspective of the object or process. Merge with the problem by asking yourself questions such as:

How would I feel if I were?

What would it say to me if it were me?

How would I feel if I were the idea I am developing?

What recommendation would it make?