OCR General Certificate of Secondary Education (GCSE) Biology Practice Exam

In Pavlov's dog experiment, what is the unconditional stimulus in stage 1?

1. A bell

2. Dog salivating

3. Food

4. Dog barking

The correct answer is: Food

In Pavlov's dog experiment, the unconditional stimulus is food. This is because the food naturally and automatically elicits a response from the dog, which is salivation. The unconditional stimulus is a stimulus that triggers a naturally occurring response without any prior conditioning. In this case, the presence of food triggers the salivation reflex in dogs, making it an essential part of understanding classical conditioning. The other options represent either responses (like salivating or barking) or a conditioned stimulus (the bell), which only begins to elicit a response after the conditioning process has taken place.