Final answer:
An organism responds to a stimulus in its environment that can trigger various forms of learning, such as classical or operant conditioning, where it associates stimuli with certain responses or behaviors and their corresponding consequences.
Step-by-step explanation:
An organism responds to any event or object in the environment, which is called a stimulus. Multiple forms of learning involve stimuli, including classical conditioning and operant conditioning. In classical conditioning, as demonstrated by Watson and Rayner's experiments with Little Albert, a fearful response to a white rat was generalised to other similar furry white objects, illustrating stimulus generalization. A neutral stimulus, by contrast, is initially a stimulus that does not elicit a response. Over time and with conditioning, this neutral stimulus can become a conditioned stimulus. For instance, in Pavlov's experiments, the sound of a tone (initially neutral) became a conditioned stimulus signaling food to the dogs. Operant conditioning involves an organism learning to associate behavior with its consequences, as when an animal learns a behavior because it leads to a positive or a negative consequence.