In Pavlov's original classical conditioning experiment, which of the following was used as the neutral stimulus (NS) before conditioning occurred?

• A. Salivation in response to food
• B. The sight of the experimenter
• C. The sound of a bell
• D. The presentation of food

Answer: (C)

Verified step by step guidance

1. Understand the concept of a neutral stimulus (NS) in classical conditioning: it is a stimulus that initially does not elicit any intrinsic response related to the unconditioned stimulus (US).
2. Recall Pavlov's classical conditioning experiment, where the unconditioned stimulus (US) was the presentation of food, which naturally caused salivation (the unconditioned response, UR).
3. Identify the stimulus that was initially neutral and did not cause salivation before conditioning; this stimulus was paired repeatedly with the food to create an association.
4. Recognize that the sound of a bell was the neutral stimulus (NS) because it did not cause salivation before conditioning but became a conditioned stimulus (CS) after being paired with the food.
5. Eliminate other options: salivation is a response, the sight of the experimenter was not the stimulus used, and the presentation of food is the unconditioned stimulus, not neutral.