In classical conditioning, which stimulus can evoke an unconditioned response the first time it is presented?

In classical conditioning, which stimulus can evoke an unconditioned response the first time it is presented?

• A. Stimulus
• B. Unconditioned Stimulus (UCS)
• C. Conditioned Stimulus
• D. Unconditioned Response (UCR)

Answer: (B)

In classical conditioning, an unconditioned stimulus is something that naturally and automatically triggers a reflexive response without any learning. Because it doesn’t require training, it can evoke the unconditioned response on the very first presentation. For example, food naturally makes a dog salivate, so the food is the unconditioned stimulus and salivation is the unconditioned response. The broader term “stimulus” is too vague, since not every stimulus causes an unlearned response. A conditioned stimulus produces a response only after conditioning with the UCS. The unconditioned response is the reaction itself, not the trigger.

In classical conditioning, an unconditioned stimulus is something that naturally and automatically triggers a reflexive response without any learning. Because it doesn’t require training, it can evoke the unconditioned response on the very first presentation. For example, food naturally makes a dog salivate, so the food is the unconditioned stimulus and salivation is the unconditioned response.

The broader term “stimulus” is too vague, since not every stimulus causes an unlearned response. A conditioned stimulus produces a response only after conditioning with the UCS. The unconditioned response is the reaction itself, not the trigger.