Ivan Pavlov was a Russian physiologist, most well known for his ground breaking study on conditioned reflexes. In this study, Pavlov carried out a series of experiments using dogs to examine how the brain can develop a conditioned response to a specific sensory stimulation and, in turn, associate it with something else. For example, as part of the experiment, Pavlov chimed a bell at or around feeding times, until eventually the dog began to salivate at the sound of the bell, whether food was there or not. This proved the brain had developed a conditioned reflex to the specific stimulus of the bell.
A game illustrating how Pavlov's theory works can be played online by clicking here.
This photograph of one of the dogs Pavlov used in his experiments was taken at the Pavlov Museum in Ryazan, Russia. A feeding tube has been inserted into the dog's muzzle to catch saliva.
Unsurprisingly, Pavlov's dogs have been the cause of much debate over the years, and the experiments have been linked to discussions around brainwashing and human conditioning. The issue of the animals' mistreatment has also been raised, with suggestions dogs were beaten and given electric shocks to test their responses. It has also been claimed, notably in the BBC programme, The Brain: A Secret History, that similar experiments were undertaken on children.