Nikolaas Tinbergen (1907 - 1988) was a noted ethologist and ornithologist who shared the 1973 Nobel Prize in Physiology or Medicine with Karl Von Frisch and Konrad Lorenz for their discoveries concerning organization and elicitation of individual and social behaviour patterns. Born in The Hague, Netherlands, he is also noted as the brother of Jan Tinbergen, who won the first Nobel Prize in Economics.

He is well known for originating the four questions he believed should be asked of any animal behaviour, which were:

  1. Immediate causation (what caused the event to occur)
  2. Development (how is this behaviour learned in the course of the animal's development)
  3. Evolution (how did this behaviour evolve)
  4. Function (why did this behaviour evolve).
They are still considered as the cornerstone of modern ethology.