Early Research on Classical Conditioning Was Performed with Dogs

Multiple Choice

Early research on classical conditioning was performed with dogs. In certain variations of this research, experimenters repeatedly presented dogs with meat powder just after ringing a bell. The dogs (who would naturally salivate after being exposed to meat powder) learned to associate the bell with the meat powder, and began to salivate as soon as they heard the bell. In this research, the bell served as a(n) ____. ​

A) unconditioned stimulus that became a conditioned stimulus
B) conditioned stimulus that became an unconditioned stimulus ​
C) neutral stimulus that became a conditioned stimulus ​
D) unconditioned stimulus that became a neutral stimulus ​