Seven people deserve mention in regard to the development of animal psychology. Together they show how positivism and belief that science is the answer to all questions became a pervasive force in psychology.
George John Romanes (1848-1894) collected anecdotal material on the importance of animals. A friend of Charles Darwin, Romanes collected animal stories and attributed human characteristics to animals (anthropomorphism).
C. Lloyd Morgan (1852-1936) took sort of a semi-experimental approach but is best known for his “cannon.” Morgan’s cannon is that higher level inferences should not be made if a lower level inference can explain the behavior. That is, scientific explanations should use the difficult explanations only when needed.
Best known for his work with apes, Robert Mearns Yerkes (1876-1956) was the premier psycho-biologist of his time. Prior to founding Yerkes Laboratories of Primate Biology, he taught at Harvard and the University of Minnesota. Yerkes also was responsible for testing army draftees in WWI and the creation of Army Alpha and Army Beta tests.
The fourth person to impact animal research was Willard .S. Small. In 1901, he invented the animal maze. It became the first practical way to systematically test animal responses, and has been widely used to study physiological and psychological issues (including motivation, learning, and memory).
Another innovation was presented by Walter S. Hunter (1889-1953). He designed an apparatus with allowed the study of memory in animals. Hunter’s delayed reaction device restrained the animal from immediately responding. Later, the animal’s memory is allowed to show what it has learned by making a choice.
Born in Germany but raised in America, Albert P. Weiss (1879-1931) attempted to explain behavior in terms of atoms, electrons and protons. His emphasis on physiological processes and an organism’s interaction with the environment helped establish bisocial behaviorism.
The German biologist Jacques Loeb (1859-1924) believed that behavior was the result of biological and chemical processes. Best known for inspiring his student (John Watson), Loeb proposed that animals are similar to plants; both react selectively to chemical and environment input.