They built on Ivan Pavlov's classic experiments on dogs, in which Pavlov would ring a bell before giving his dogs food. (discovermagazine.com)
In one classic experiment by economist Ernst Fehr at the University of Zurich, Switzerland, people were given # 20 and asked to share as much or as little of it as they liked with an anonymous partner whose identity would never be revealed and who would never know the giver's identity. (newscientist.com)
However, classic experiments where the position of different growth plates was interchanged suggested that the local environment can modulate this genetic programme. (sciencedaily.com)