Calvin was chased and assaulted by an aggressive rooster when he was barely 3 years old. As an adult, he still gets little twists in his stomach when he hears the word rooster, and he claims that birds make him nervous.

What is the unconditioned stimulus in this example?

A. The word rooster

B. The rooster who attacked Calvin

C. Twists in Calvin's stomach/feeling nervous

D. Calvin

B. The rooster who attacked Calvin

Explanation:

According to classical conditioning, the conditioned stimulus is the word rooster while the unconditioned stimulus is the rooster that attacked Calvin and the conditioned response is the twists in Calvin's stomach/feeling nervous.

Classical conditioning is a type learning whereby an unconditioned stimulus (the rooster who attacked Calvin) is associated with a conditioned stimulus (the word rooster) to elicit a conditioned response (twists in Calvin's stomach/feeling nervous) in a the subject.