In Aldous Huxley's Brave New World, infants develop a fear of roses after roses are presented with electric shock. In this fictional example, the presentation of the roses is the?

The roses are the conditioned stimulus.

Explanation:

In the classical condition theory by Ivan Pavlov, a conditioned simulus (the rose in this example) is associated with an unconditioned simulus (the shock), and provokes a conditioned response (fear).

A famous experiment involves Pavlov ringing a bell every time he was going to feed a dog. In time, the dog started salivating just by hearing the sound of the bell.