Final answer:
The conditioned response increases during acquisition as the association between the conditioned and unconditioned stimuli strengthens, and it decreases during spontaneous recovery, where the conditioned response reappears but is weaker compared to the acquisition phase.
Step-by-step explanation:
The strength of the conditioned response (CR) increases during acquisition and decreases during spontaneous recovery. This can be understood within the context of classical conditioning, where a neutral stimulus (conditioned stimulus) is repeatedly paired with an unconditioned stimulus until it elicits the conditioned response. During acquisition, the association between the conditioned stimulus and the unconditioned stimulus strengthens, making the conditioned response more pronounced.
When conditioning is halted, and the conditioned stimulus is presented alone, the conditioned response may start to weaken or extinguish, shown by the decrease in response. This process is known as extinction. However, after a period of time with no exposure to the conditioned stimulus, the conditioned response can suddenly reappear. This reappearance, without the pairing of the conditioned stimulus with the unconditioned stimulus, is known as spontaneous recovery. The conditioned response is weaker in spontaneous recovery compared to the acquisition phase.