B.F. Skinner on Horses:
There is definitely something wrong with the way the horses are handled," wrote Skinner (1983, p. 82) after making several visits to a horse barn.
"Their control is almost exclusively aversive. I am going to talk to the teacher in charge of the horses and unless she thinks it likely to 'spoil' the present training, I'll try to ... shape some behavior" (p. 82).
Armed with a frying pan and a bicycle horn, Skinner began to shape the behavior of a horse named Mama. Using the frying pan to feed small amounts of oats or hay to Mama and the horn's sound as a conditioned reinforcer, he shaped Mama to turn her head to one side.
Later, Skinner could hold Mama's head so that a bridle could be placed on her head and a bit placed in her mouth. But soon his investigation was halted after a rider in the barn informed him that he had violated a fundamental rule of horse training: "You must not be nice to a horse."
By positively reinforcing desired behavior, he was found guilty of "spoiling" (p. 83) the horse. He abandoned his investigation.
These observations, presented in Skinner's autobiography, well characterize the attitudes of horse handlers today: Few types of behavior are controlled by positive reinforcement.