Learning refers to a relatively permanent change in behavior brought about be experience. it does not include changes that occur due to maturation. For example, pubertal changes are maturational. Some learning occurs in formal contexts such as school while other learning occurs through observing others.
There are two general approaches to learning theory. One is classical conditioning in in which two stimuli become associated. Pavlov's was the most famous classical conditioning experiment. In that experiment, his dog came to associate the sound of the bell with dinner and thus he learned to salivate. When you read Pavlov's study, keep in mind that conditioned means learned and unconditioned means unlearned.
One area that has been studied extensively in terms of classical conditioning is food aversion. Does some food make you gag? Think back to what happened the first time you gagged on that food. It probably wasn't related to the food per se.
The other major school of learning is that of B.F. Skinner. Skinner's work involves a focus on reinforcers and how they make it likely that a behavior will repeat. Remember that any reinforcer, be it positive or negative, will increase the likelihood of a behavior being repeated. Any punishment is intended to extinguish a behavior.
If in first grade, your teacher had a chart in front of the room where you received stars for good behavior, that was a result of Skinnerian theory. Positive reinforcers are given to increase behavior. Negative reinforcers are escapes from unpleasant things that increase behavior. Why do you put on your seat belt? Is it to escape that annoying dinging? If so, you have been negatively reinforced.
There is also observational or social learning that can occur. We can learn behavior through watching others, if we think the other is important (i.e. a role model). Social learning theory, formulated by Bandura, includes the use of reinforcement and punishment.
Learning theory has been applied in many areas of life. Can you think of some specific examples?