Final answer:
Sally is learning to overcome her phobia of snakes through modeling, which is a type of observational learning where she watches another child being reinforced.
Step-by-step explanation:
Sally learns to overcome her phobia of snakes by observing another child who is reinforced with a piece of candy each time he picked up the snake. This is an example of observational learning, specifically known as modeling. Modeling is a type of observational learning where a person learns to imitate or adopt a behavior by observing someone else being rewarded or punished for that behavior. In the scenario described, the second child acts as a model whose behavior is reinforced, thus providing an example for Sally to follow. This type of learning is distinct from operant conditioning, where the learner would be directly reinforced or punished, and classical conditioning, where a neutral stimulus becomes associated with a response.