Final answer:
An uncontrolled stimulus in Pavlov's dog experiment is the meat powder, and the uncontrolled response is the dogs' salivation. A controlled stimulus is the ringing of a bell after conditioning, and the controlled response is the dogs' salivation upon hearing the bell.
Step-by-step explanation:
In classical conditioning scenarios like the one developed by Ivan Pavlov, an uncontrolled stimulus (or unconditioned stimulus) leads to an uncontrolled response (or unconditioned response), while a controlled stimulus (or conditioned stimulus) eventually leads to a controlled response (or conditioned response). In the dog scenario, the uncontrolled stimulus is the meat powder which naturally makes the dog salivate without prior learning. The uncontrolled response is the dogs' salivation when they detect the meat powder. Over time, Pavlov conditioned the dogs to associate a controlled stimulus (the ringing of a bell) with receiving food. After conditioning, the controlled response occurs when the dog salivates upon hearing the bell, even in the absence of the meat powder. Pavlov's experiments highlighted the process by which a neutral stimulus, through association with an uncontrolled stimulus, could elicit a response similar to the uncontrolled response, a process known as classical conditioning.