Learning is necessary for all animals, it helps the survival of the fittest and helps adjust to the ever-changing environment. Learning is the association between two events together. Classical conditioning and operant conditioning both work with associating events together.
Thanks to Ivan Pavlov, the accidental discovery of classical or 'Pavlovian conditioning' led to a whole new section of learning. Classical conditioning is what happens when the learner learns to associate stimulus together through involuntary or automatic responses.
Ivan Pavlov was a veterinarian who accidentally discovered that his dogs began to salivate before food was presented, thus his famous experimented with dogs begun in the early 20th century. What Pavlov did in his experiment was that he would have a dog that would salivate when presented with meat powder. The unconditional stimulus is a stimulus that naturally causes a response; the meat powder in Pavlov's experiment was the unconditional response. The unconditioned response is the natural reaction to a stimulus, in Pavlov's experiment, the dog's salivation to the sight of food and the no salivation response to the tuning fork are the unconditioned stimulus. Pavlov would then separately strike a tuning fork and the dog's natural response to the tone would be to not salivate. During conditioning, Pavlov hit the tone then he presented the dog the meat powder shortly after, which would cause the dog to salivate, after doing this a number of times, the dog would associate the tone of the tuning fork to food. After the conditioning, the dog would be able to salivate to the tuning fork's tone without even having to see the meat chowder. The conditional stimulus is the learned reaction to a neutral stimulus, in Pavlov's experiment; this would be the tuning fork. The conditional reaction would be the dog's...