Transposition is a form of relational learning in which a learned relational response (e.g., smaller) transfers to a novel pair of stimuli after a simultaneous stimulus discrimination training.
The first transposition experiment has been designed by Wolfgang Köhler (1918/1938). In these experiments, chickens and chimpanzees were presented with a two-alternative simultaneous discrimination in which a response to a darker shade of gray was not reinforced and a response to a lighter shade of gray was reinforced (or vice versa). Once the original discrimination was learned, the subjects were given a choice between the original, light shade of gray and a novel, still lighter, shade of gray. Köhler proposed that learning to respond to a specific shade of gray (absolute responding) should result in a preference for the original gray shade; however, learning to respond to the relationship between the two shades (relational responding)...