Learning may be defined as a relatively permanent change in behavior, capability, or attitude that is acquired through experience and cannot be attributed to illness, injury, or maturation.
We learn in three different ways: Classical conditioning, operant or instrumental conditioning, and observational learning.
Classical or Pavlovian conditioning:
stimulus -- Any event or object in the environment to which an organism responds; plural is stimuli.
unconditioned stimulus (US): A stimulus that elicits a specific response without prior learning.
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