Comparative Psychology

Problems of genesis concern the evolutionary and developmental histories of behavioral patterns. Those of control relate to the immediate factors, both inside and outside of the animal, affecting behavior. The con­sequences of behavior can be those for the animal itself, other animals, or the environment, but concern espe­cially the reproductive success of the animal displaying the behavioral pattern. Such reproductive success, or biological fitness, feeds back to affect the evolution of the behavior and the species.

Psychology is sometimes defined as the study of hu­man behavior. In such a context, the notion of animals as subjects of psychological study appears paradoxical. However, animal research has been a part of psychol­ogy since its differentiation as a distinct branch of in­quiry and has contributed much to the field during that time.

The term comparative psychology has created much difficulty. Through much of the history of the field it has been used in reference to all research on nonhuman animals. The term is better used, however, only in reference to a part of that subdiscipline. Animal re­search targeted strictly at understanding the process of learning and that aimed at physiological mechanisms are important endeavors but are best treated as differ­ent from true comparative psychology. The term animal psychology can be used as an umbrella for all three.

The term comparative is, however, somewhat mis­leading in the description of the field. Some authors have proposed that in order to qualify as comparative, research must entail overt comparisons among different animal species. This perspective has been generally re­jected. What is critical for research in comparative psy­chology is the broad biological framework in which the research is placed. Problems are framed in relation to the evolution and development of behavior conceived broadly. Some early pioneers of comparative psychol­ogy, C. Lloyd Morgan and Linus Kline, proposed that the field be termed zoological psychology. This term is more descriptive of the comparative psychology that has evolved because the problems studied, modes of thinking. and interpretations of comparative psychol­ogists overlap those of many zoologists interested in an­imal behavior. Comparative psychologists have differed from zoologists in that their problems have often been generated and interpreted in relation to those of the psychology of human behavior. Thus, comparative psy­chologists have had to tread a narrow line as they work with a vision of psychological breadth. on the one hand. while placing their work in broad biological per­spective, on the other.

History of Comparative Psychology

Thought concerning the relationship between humans and nonhuman species can be seen early on in intel­lectual history. Aristotle wrote of the Scala naturae, be­lieving that species could be placed along a single con­tinuum from the lowest to the highest, a view that is rejected today. Prominent among the many philoso­phers who addressed these issues was Rene Descartes, who believed there to be a fundamental dichotomy be­tween the human soul and the reflex mechanisms gov­erning animal behavior.

The true antecedents of comparative psychology can be seen among British scientists of the nineteenth cen­tury. The work of Charles Darwin was critical in estab­lishing the relationship between human and nonhuman species, thus rendering a comparative psychology reasonable. Darwin’s protégé, George John Romanes, and C. Lloyd Morgan followed Darwin in applying ev­olutionary principles to the study of behavior. They saw continuity between the instincts and intelligent acts of humans and those of other species. Also in England, Douglas A. Spalding began experimental studies of the factors important in the development of behavior.

Experimental studies in comparative psychology de­veloped in the United States around the turn of the century. Under the influence of psychologists such as William James at Harvard and G. Stanley Hall at Clark University, psychologists such as Edward L. Thorndike, Robert Yerkes, Linus Kline, and Willard Small conducted experimental studies of animal be­havior in a psychological context. Margaret Floy Washburn (1908), with a Ph.D. degree from Cornell University, wrote The Animal Mind, which would be­come the standard textbook in the field for 25 years. John B. Watson, with a University of Chicago Ph.D. degree, worked in the field of developmental psycho-biology, conducted field studies of the behavioral pat­terns of noddy and sooty terns, and eventually devel­oped the school of behaviorism.

After a bit of a lull during and after World War I. comparative psychology flourished during the 1930s. Robert Yerkes opened the facility that would become the Yerkes Laboratories of Primate Biology in Orange Park, Florida in 1930, It would become the leading fa­cility for research on the great apes and attract scien­tists from all over the world. Among Yerkes’s associates, H. C. Bingham. Henry Nissen, and C. Ray Carpenter pioneered field studies of primate behavior, thus open­ing the door to a productive line of interdisciplinary research. During this period T. C. Schneirla began his research, including numerous field studies, on the be­havior of ants; Frank A. Beach began his long program of work on the neural and hormonal determinants of instinctive patterns in mammals; and Harry E Harlow began work on such problems as development and learning in monkeys. Also during this period various new textbooks, such as E A. Moss’s (1934) Comparative Psychology, appeared. The field was in full swing.

The leaders who matured during the 1930s pro­duced numerous students who continued to develop the field. Three post-World War II developments greatly af­fected comparative psychology. The first was the strengthening of ties with European ethology, as rep­resented by Konrad Lorenz, Nikolaas Tinbergen, and their colleagues. These interactions increased compar­ative psychologists’ interest in problems of evolution and adaptive significance and in instinctive behavior. The second was the development during the 1970s of the field of behavioral ecology/sociobiology. This ap­proach worked from such principles as (i) natural se­lection works at the level of the individual animal, and (2) one’s genetic interests are represented in close kin as well as in one’s self. The study of animal behavior was revolutionized as a result and helped focus theory in psychology on issues of biological currency. The third was the “cognitive revolution.” which resulted in a weakening of the hold of more reductionistic forms of behaviorism on the field. Although cognitive studies had always been a part of comparative psychology, they moved from the background to the foreground during this period. Today, comparative psychology flourishes as a rather diverse but productive field.

Representative Research in Comparative Psychology

The main research categories in comparative psychol­ogy are four in number. They begin with efforts to iden­tify the evolution of behavioral patterns and continue with understanding the effects of various stimuli, con­sidering the consequences of behavior, and investigat­ing animal cognition.

Genesis

The study of evolutionary history entails efforts to trace the history of behavioral patterns through their evolution in different species. For exam­ple, Greene and Burghardt (Science, 1978) traced the probable history of different patterns of constriction in ancient and modern snakes.

The development of behavior entails the continuous, dynamic interaction of genes, environment, and the or­ganism in an epigenetic process. Studies of genetic ef­fects on behavior have traditionally concerned inbred strains, genetic selection experiments, and hybridiza­tion. More powerful techniques have recently become available with the development of modern molecular genetics. The influence of important early experience and the changing baseline on which that experience acts have been the focus of comparative developmental research. An active research area concerns the ontog­eny of bird song, where genes and environmental input interact in diverse and complex ways in different spe­cies.

Control

Many influences on behavior are contem­poraneous, or nearly so, with the behavior. Many com­parative psychologists study the effects of particular stimuli, such as the displays and calls of various spe­cies, on the individual of concern.

Comparative psychologists are increasingly interact­ing with scientists from related fields to also study in­ternal mechanisms that control behavior. There is much interest in sensory function within the animal’s skin. The study of the nervous system as it affects and is affected by behavior has become quite prominent with the development of behavioral neuroscience. Hor­monal determinants and consequences of behavior have received much interest. An important trend is the ability to monitor and manipulate hormonal levels un­der field conditions so that effects can be examined in their full natural context.

Consequences

Although many consequences of behavior are important, effects on reproductive success have taken center stage because of their importance to evolutionary change. Such areas as prey-predator in­teraction and reproductive behavior have received much attention because of the obvious relationship to survival and reproductive success. In the latter case, modern techniques allow the psychologist to determine which of several possible males is the father of young animals. This enables the study of the tie between ag­gressive, sexual, and parental behavior and successful genetic transmission.

Animal Cognition

Studies of animal cognition have been part of comparative psychology for many years, as in the work of Wolfgang Kohler. Walter Hun­ter, and Robert Yerkes. In recent years, however, there has been a rebirth of interest in cognitive studies. One group of students of comparative cognition works within a behavioristic context in the study of such phe­nomena as attention, memory, timing, concept forma­tion, and counting. Others. following the lead of ethologist Donald Griffin. are developing a field of cognitive ethology which advocates a return to mentalistic con­cepts such as consciousness, intention. and mind. Stud­ies of language learning by chimpanzees, such as those of the Gardners with American sign language, Pre-mack with small plastic “words,” and Rumbaugh and Savage-Rumbaugh with symbols in a “Yerkish” lan­guage, and of other species. such as dolphins. parrots, and sea lions. have been especially influential in the field of animal cognition.

Comparative Psychology References:

1. R. (1984). From Darwin to behaviourism: Psychology and the minds of animals. Cambridge: Cambridge Uni­versity Press. A study of the history of comparative psychology with an emphasis on learning and behavioristic approaches.
2. D. A. (1978). Comparative animal behavior. New York: McGraw-Hill. A textbook in comparative psy­chology.
3. D. A. (1984). Comparative psychology in the twen­tieth century. Stroudsburg. PA: Hutchinson Ross. A comprehensive study of the history of comparative psy­chology.
4. Dewsbury, D. A. (Ed.). (1990). Contemporary issues in com­parative psychology. Sunderland, MA: Sinauer. A selec­tion of research articles by some leading comparative psychologists.
5. Dewsbury, D. A. (1992). Triumph and tribulation in the history of American comparative psychology. Journal of Comparative Psychology, 106, 3-19. A survey of the dif­ficulties experienced and the accomplishments of com­parative psychologists in the United States.
6. Maier, R. (1998). Comparative animal behavior: An evolution­ary and ecological approach. Boston: Allyn & Bacon. A recent textbook in comparative psychology.
7. Moss, A. (Ed.). (1934). Comparative psychology. New York: Prentice Hall. A comprehensive treatment of compar­ative psychology as it was conceptualized in the 1930s.
8. H. L. (1987). Introduction to comparative cognition. New York: Freeman. A textbook in comparative cogni­tion.
9. Washburn, M. F. (1908). The animal mind: A text-book of comparative psychology. New York: Macmillan. A stan­dard textbook in comparative psychology during the early part of the century.
10. E. A. (1993). Comparative cognition: Begin­ning the second century of the study of animal intel­ligence. Psychological Bulletin, 113, 211-228. A position paper for the study of animal cognition near the end of the twentieth century.