Here is a nice experiment with a dog (no animal was hurt)... In front of the dog, there are two people, one generous with food and one... Not so generous. A person goes once to the generous and once to the non-generous to ask for food. The first gives food and the second denies. Then the woman leaves the room and the dog is set free. yes, you guessed correct, the dog knows exactly where to go to get food... Read more here.