Final answer:
In the Little Albert experiment, Watson and Rayner investigated classical conditioning in a child's fear response. They conditioned Little Albert to fear a white rat by pairing it with a loud sound.
Step-by-step explanation:
In the Little Albert experiment, Watson and Rayner investigated classical conditioning in a child's fear response. They conditioned Little Albert to fear a white rat by pairing it with a loud sound. The loud sound (UCS) was the unconditioned stimulus that naturally elicited fear (UCR) in Little Albert. The white rat (CS) became the conditioned stimulus that elicited fear (CR) in Little Albert after being paired with the loud sound.