Classical Conditioning
First proposed and studied by Ivan Pavlov, classical conditioning is one form of learning in which an organism "learns" through establishing associations between different events and stimuli. For example, when a neutral stimulus (such as a bell) is paired with an unconditioned stimulus (such as food) which produces some involuntary bodily response all on its own (such as salivating), the neutral stimulus begins to trigger a response by the organism similar (some salivation) to that produced by the unconditioned stimulus. In this way, the organism has "learned" that the neutral stimulus equals something good (just like the unconditioned stimulus).