If certain parts of the body need food, they must collect. See the right bottom picture. Positive signs (+) represent the "collect signal". Negative signs (-) represent the "repel signal". In this picture, we see more (+) than the (-). Therefore this action forces the person to eat food.
Request for food . most neurons are positive

If your body does not need the hamburger, your neurons will transmit negative signals(-) from body parts to your brain, causing you to repel from the burger.
Reject signs causes you to repel from the food

If you have more positive signals (+), you eat. So you reach for the hamburger with your hands. Now wait! How did the hands get involved?

Remember this picture? (Please wait for picture to move.)
reach for food
The metal rod and the spring represent your hand. For more review over this phenomenon, PRESS HERE.

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