Animal Experimentation

The use of destructive and nondestructive testing upon various animal species in order to better understand the mechanisms of human and animal diseases, behaviors, emotions, and thought processes.

Animal experimentation, also called animal testing, animal research, and in vivo experimentation, includes a wide variety of studies ranging from simple observation of a species in its natural habitat to learn more about it to pure and applied research. Pure research using animals includes developmental biology, genetics, and ethology (the study of animal behaviors, communication patterns, and instincts); applied research includes medical research, drug testing, toxicology studies, and xenotransplantation (the use of animal tissues for transplantation into humans). Other fields in which animals are used are education (graduate education of biologists and health professionals, including veterinarians) and animal husbandry (breeding).

Animal experimentation is a subject of concern because the mapping of the human genome, completed in 2003, helped to show how much humans have in common, genetically speaking, with other animal species. Biologists now know that chimpanzees share at least 98.4% of the same DNA as humans. Gorillas have a genetic composition which is at least 97% consistent with that of humans. Sequencing of the genomes of other non-primate animals in 2007 showed that the domestic cat shares 90% of its genome with humans while dogs share 82%. On the one hand, increased understanding of these genetic similarities has enhanced interest in animal experimentation; for example, cats and humans share a common susceptibility to nearly 100 different infectious diseases, and studying the immune system of the cat has already added to researchers’ understanding of such disorders of the human immune system as HIV infection.

On the other hand, this newfound awareness of human biological kinship with other animals, taken together with evidence of animals as sentient beings capable of a wide range of emotions and thought processes, has led scientists and animal activists to search for alternative ways to study behavior without victimizing animals. Although most psychology research does not involve deadly disease or experimental pathology, it often involves unrelenting or quantitative mental, physical, and psychological stress—all of which animals are capable of experiencing.


Centuries later, Charles Darwin's theory of evolution in 1859 became the scientific rationale for using animal experiments to learn more about humans. In the late nineteenth century, Ivan Pavlov's experiments in the development of conditioned responses in dogs (salivation) helped to foster an increasingly authoritative school of psychology known as behaviorism. The American pioneer in the use of animals in learning experiments was Edward Thorndike (1874–1949); his 1898 doctoral dissertation in psychology was the first ever written on nonhuman subjects. The contemporary human treatment regimen known as behavior modification is fashioned from parallels drawn on these early experiments in operant conditioning.

In 1876, Great Britain passed the British Cruelty to Animals Act, which regulated animal experimentation. Still, behaviorist thinking at that time denied animals any psyche or emotion. Academic journals described animal behavior only in terms of physiologic response to stimuli, with no mention of any psychological consequence.

In later years, the behaviorist theories were overshadowed by the development and spread (from Europe to the United States) of ethology, which concerns itself with genetic predisposition, or innate/ instinctive behavior and knowledge. This theory continues to prevail in the United States, but in terms of relevance, it is tempered by the reality that between 85 and 90% of all animal experimentation is conducted on species not sufficiently similar to humans to draw dispositive parallels. The majority of all animal research in the field of psychology is conducted on various rodent species or birds as laboratory subjects.

Australian philosopher Peter Singer made the case for an end to animal experimentation with his 1975 book, Animal Liberation. Coinciding with his book was the comprehensive and sensitive research of such ethologists as Jane Goodall and Dian Fossey, who suggested that primates were capable of a full spectrum of emotions, including love, sorrow, jealousy, humor, and deceit. These animals also learned to communicate with humans by using over 300 learned signs in American Sign Language. Studies with other species produced similar results. During the late 1990s, an African gray parrot named Alex, who was being studied at the Arizona State University, fell ill and was required to spend the night alone at a veterinary clinic. When his keeper attempted to leave the room at the clinic, Alex cried out, “Come here, I love you, I'm sorry. Wanna go back.” Such examples of the yetunknown extent of emotional, psychological, and behavioral capacity in other species have cast new doubts on the scientific rationale for the continuation of captive animal experimentation.

Current situation

Types of research

Animal experimentation is still widely used in psychological research. Animals are used in projects of many types, but according to the American Psychological Association (APA), less than 10% of pure psychological research uses animals as subjects. This estimate does not include animal subjects used for crossover medical experimentation, such as in the related field of neuropsychology. Best estimates for the total number of animal subjects in all medical/psychological research in the United States is about 100 million per year, including 100,000 nonhuman primates, 20,000 cats, and 70,000 dogs, according to figures given by the U.S. Department of Agriculture for 2014. Of the animals used in psychological research, 90% are rodents (rats and mice) and birds.

The types of research in which animal testing is used as of 2015 include:

Legislation and professional regulation

The Animal Welfare Act (Laboratory Animal Welfare Act of 1966, P.L. 89-544) was signed into law by then-President Lyndon Johnson in August 1966. The Act covers the humane housing and treatment of cats, dogs, hamsters, rabbits, nonhuman primates, and guinea pigs but specifically excludes rats and mice, birds, and cold-blooded animals. The Act specifies that all research facilities in the United States must have an animal welfare committee that includes at least one licensed veterinarian and one person not affiliated with the facility, and that complete inspections must be carried out every six months. In addition to the federal government, both the American Psychological Association (APA) and the American Veterinary Medical Association (AVMA) have issued position papers on the ethics of animal experimentation; these may be accessed from the websites referenced in Resources. The APA also has a standing committee called the Committee on Animal Research and Ethics (CARE).

Concerns about cruelty have led to the search for alternative methodologies. Of great promise in this regard is computer simulation technology. As early as 1996, psychology students were able to study “shaping” and partial reinforcement in operant conditioning, by using a computer-created virtual rat named Sniffy. On the other hand, although the use of computer simulation and other alternatives to dissection have lowered the use of cats, dogs, rabbits, and hamsters in research, the rapid advances in genetics made possible by high-throughput sequencing since 2005 have led to actual increases in the worldwide use of mice and zebrafish for experiments in genetic engineering. The development of genetically modified (GM) knockout mice in particular has led to an explosion in the number of genetic experiments, particularly in China.


The systematic study of animal behavior, most often under natural conditions.
The complete genetic material of an organism, including both its genes and the noncoding sequences of its DNA.
Knockout mouse—
A genetically modified mouse in which researchers have deliberately inactivated (“knocked out” ) a specific gene and replaced it with an artificial DNA sequence.
Any mammal belong to the order Primates. Living primates include lemurs, apes, chimpanzees, macaques, gibbons, howler monkeys, baboons, and humans.
The transplantation of living cells, tissues, or organs from a member of one species to a member of a different species.

See also Behaviorism ; Ethical treatment of animals ; Ethology ; Thorndike, Edward.



Guille´ n, Javier. Laboratory Animals: Regulations and Recommendations for Global Collaborative Research. Amsterdam, The Netherlands: Academic Press, 2014.

Lyons, Dan. The Politics of Animal Experimentation. New York: Palgrave Macmillan, 2013.

Newton, David. The Animal Experimentation Debate: A Reference Handbook. Santa Barbara, CA: ABC-CLIO, 2013.


Browning, H.M., et al. “Common Cancer in a Wild Animal: the California Sea Lion (Zalophus californianus) as an Emerging Model for Carcinogenesis.” Philosophical Transactions of the Royal Society of London, Series B, Biological Sciences 370 (July 19, 2015): pii: 20140228.

Cattaneo, C., et al. “Animal Experimentation in Forensic Sciences: How Far Have We Come?” Forensic Science International, July 15, 2015 [E-publication ahead of print].

Olsson, I.A., and N.H. Franco. “Europe: Animal Studies Must Be Useful, Says Public.” Nature 523 (July 2, 2015): 35.

Stokes, W.S., et al. “Recent Progress and Future Directions for Reduction, Refinement, and Replacement of Animal Use in Veterinary Vaccine Potency and Safety Testing: A Report from the 2010 NICEATM-ICCVAM International Vaccine Workshop.” Developments in Biologicals 134 (2012): 9–21.

Van Norman, G.A. “A Matter of Mice and Men: Ethical Issues in Animal Experimentation.” International Anesthesiology Clinics 53 (Summer 2015): 63–78.


American Psychological Association (APA). “Guidelines for Ethical Conduct in the Care and Use of Nonhuman Animals in Research.” (accessed August 12, 2015). (accessed August 12, 2015).

American Veterinary Medical Association (AVMA). “AVMA Policies Related to Research.” This page contains links to 22 policy statements and position papers on the use of animals in biomedical research. (accessed August 12, 2015).


APA Committee on Animal Research and Ethics (CARE), 750 First Street, NE, Washington, DC, United States, 20002-4242, (202) 336-6000, Fax: (202) 336-5953,,

American Veterinary Medical Association (AVMA), 1931 North Meacham Road, Suite 100, Schaumburg, IL, United States, 60173, (800) 248-2862, Fax: (847) 9251329, .