Classical Conditioning

Classical conditioning, made famous by Ivan Pavlov’s experiments with dogs, creates a learned association between a neutral,  naturally-occurring stimuli (a bell), causing the neutral stimulus to become a conditioned stimulus (a bell meaning food) when it triggers an automatic response (dogs salivating). In contrast to associative learning (encompassing a wider range of learning processes connecting stimuli), classical conditioning is a specific type of associative learning where a neutral stimulus becomes a meaningful stimulus, leading to a learned response. Also see: Reward System and Operant Conditioning. In brief: 

• Neutral stimulus initially does not elicit a response (bell sounds). 
• Unconditioned stimulus (UCS) naturally produces a response (food). 
• Unconditioned response (UCR) is the natural response to the unconditioned stimulus (salivation). 
• Conditioned stimulus (CS) has replaced the previously neutral stimulus now that it’s associated with the unconditioned stimulus. 
• Conditioned response (CR) is the learned response to the conditioned stimulus.