as a note: in human learning, and to a degree, animal learning, the unit of behavior that is reinforced depends on the contingencies— an interesting example: a pigeon might be trained to respond in a 3x3 grid (9 choices) differently than the last time to get reinforcement. At first the response learned is do different than the last time, but as the requirement gets too long, the memory capacity is exceeded— and guess what, the animal learns to respond randomly— eventually maximizing its reward