Every weekend during the summer, Bradon's family has a party. They invite over lots of friends and spend time playing games, swimming, and eating barbecue. Now whenever Bradon smells someone cooking barbecue he notices that he feels happy. Identify the unconditioned stimulus.

The answer is the family parties.

Explanation:

In classical conditioning, a conditioned stimulus (the smell of barbecue) is associated with an unrelated consequence, called unconditioned stimulus (the parties). This produces a reaction known as conditioned response (happiness).

It's important to recognise that unconditioned stimuli do not need a different stimulus to produce a response, but they can be paired with an unrelated object or situation in order to condition it.

Party with family and friends

Explanation:

Brandon's happiness in this case is not primarily tied alone to food but rather he enjoys the atmosphere of the fellowship the family shares when they hangout, when he views all this with the love and care shared and when meals are prepared they all make him joyous as the moments are memorable.