"Comparative psychology" refers to the scientific study of the behavior and mental processes of nonhuman animals (especially as these relate to the adaptation, evolution, and development of behavior), which can lead to a deeper and broader understanding of human psychology. Research in this area addresses many different issues, uses many different methods, and explores the behavior of many different species, from insects to primates.
Comparative psychology is sometimes assumed to emphasize cross-species comparisons, including those between humans and animals. However, some researchers caution that direct comparison with human psychology should not be the sole focus of comparative psychology, and that intense focus on a single organism to understand its behavior is also valuable. Research in comparative psychology is usually studied under controlled laboratory experiments in order to discover general principles of behavior.
History
The earliest works on "the social organization of ants" and "animal communication and psychology" were written by al-Jahiz, a 9th-century Afro-Arab scholar who wrote many works on these subjects. The 11th-century Arabic writer Ibn al-Haytham (Alhazen) wrote the Treatise on the Influence of Melodies on the Souls of Animals, an early work dealing with the effects of music on animals. In the treatise, he demonstrates how a camel's pace can be hastened or slowed with the use of music. Through the 19th century, a majority of scholars in the Western world continued to believe that music was a distinctly human phenomenon, but experiments since then have vindicated Ibn al-Haytham's view that music does indeed have an effect on animals.
Charles Darwin was central in the development of comparative psychology; in fact, the field is often separated into pre- and post-Darwin phases because his contributions were so influential. Darwin's theory led to several hypotheses, one being that the factors that set humans apart—such as higher mental, moral, and spiritual faculties—could be accounted for by evolutionary principles. George John Romanes was also highly influential in the development of comparative psychology; following Darwin's work, he set out to prove that animals had a “rudimentary human mind.”
Topics of Comparative Psychology
Comparative psychologists study many issues, and typical questions involve the similarities and differences among how humans and animals behave in their environments and day-to-day lives. The field examines such things as individual behavior, interaction with the environment, reproduction, grooming and hygiene, how different life forms learn, forms of motivation, and mental capacities. Researchers who study animal cognition are interested in understanding the mental processes that control complex behavior, and much of their work parallels that of cognitive psychologists working with humans.
A wide variety of species have been studied by comparative psychologists. Ivan Pavlov's early work used dogs; Edward Thorndike began his studies with cats; and B. F. Skinner introduced the use of pigeons in his work. American comparative psychologists quickly shifted to the more economical rat, which remained the almost invariable subject for the first half of the 20th century and continues to be used today. There has always been interest in studying various primate species; important contributions to social and developmental psychology were made by Harry F. Harlow's studies of maternal deprivation in rhesus monkeys.
The brain of a cat
A wide variety of species have been studied by comparative psychologists in order to gain insight into the behavior and mental processes of nonhuman animals.