Intermittent reinforcement (aka hot and cold) is the STRONGEST type of reinforcement. There have been studies done with rats to demonstrate its addictive nature. Two different groups of rats in cages had a lever to press which produced food pellets. In the first group every time they pressed the lever a pellet came out – these rats were fine and just learned to press the lever when they were hungry. The second group of rats the pellets came out intermittently and the rats ended up pressing the lever on repeat until they died. Until they DIED guys! That’s how strong intermittent reinforcement is.