On December 10 1904 the Russion physiologist Ivan Pavlov received a nobel price for his research into how the digestive system works.

His experiments, which he carried out on dogs, have shown that nerve messages trasmitted from the brain play a part in the digestion of our food.

Scientists however are more excited by what Pavlov calls his "conditoned refles" experiments, which may be of major importance for understanding how we learn.

Pavlov has found that if a bell is rung each time a dog is fed it will eventually salivate when it hears the sound of the bell alone, even if no food is visible.

If the same is trueof humans, it suggests that kind of behavior can be learned just like any skill.