Ivan Pavlov; Pavlov's Dogs

Ivan Petrovich Pavlov was an important Russian psychologist; most well-known for his work in classical conditioning and for the concept of the "conditioned reflex." This idea was developed with the aid of his assistant Ivan Filippovitch Tolochinov in 1901. Pavlov discovered that when a specific type of sound was made in conjunction with the presentation of food to dogs, the dogs would eventually associate the sound with the coming of food, and salivate at the hearing of the tone. This was coined the "conditioned reflex."

Pavlov's work with classical conditioning largely influenced how humans perceived themselves, and these key concepts still remain a fundamental part of behavior therapy. Pavlov's research on "conditional reflexes" also became pivotal in literature of the time, such as in Aldous Huxley's dystopian novel Brave New World.