Introduction (Psychology and Mental Health)
Before the general acceptance of Charles Darwin’s theory of evolution in the late nineteenth century, in much of the Western world, animals were considered to be soulless machines with no thoughts or emotions. Humans, on the other hand, were assumed to be qualitatively different from other animals because of their abilities to speak, reason, and exercise free will. Therefore, nothing could be learned about the mind by studying animals.
After Darwin, however, people began to recognize that although each species is unique, the chain of life is continuous, and species have similarities as well as differences. Because animal brains and human brains are made of the same kinds of cells and have similar structures and connections, it was reasoned, the mental processes of animals must be similar to the mental processes of humans. This new insight led to the introduction of animals as psychological research subjects around 1900. Since then, animal experimentation has taught much about the brain and the mind, especially in the fields of learning, memory, motivation, and sensation.
Psychologists who study animals can be roughly categorized into three groups: biopsychologists (psychobiologists), learning theorists, and ethologists and sociobiologists. Biopsychologists, or physiological psychologists, study the genetic, neural, and hormonal controls of behavior, for example, eating behavior, sleep, sexual behavior, perception,...
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Reasons for Using Animal Subjects (Psychology and Mental Health)
Psychologists study animals for a variety of reasons. Sometimes they study the behavior of a particular animal to solve a specific problem. They may study dogs, for example, to learn how best to train them as police dogs; chickens to learn how to prevent them from fighting one another in coops; and wildlife to learn how to regulate populations in parks, refuges, or urban areas. These are all examples of what is called applied research.
Most psychologists, though, are more interested in human behavior but study animals for practical reasons. A developmental psychologist, for example, may study an animal that has a much shorter life span than humans do so that each study takes a much shorter time and more studies can be done. Animals may also be studied when an experiment requires strict controls; researchers can control the food, housing, and even social environment of laboratory animals but cannot control such variables in the lives of human subjects. Experimenters can even control the genetics of animals by breeding them in the laboratory; rats and mice have been bred for so many generations that researchers can special order from hundreds of strains and breeds and can even obtain animals that are basically genetically identical.
Another reason psychologists sometimes study animals is that there are fewer ethical considerations than in research with human subjects. Physiological psychologists and...
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Scientific Value (Psychology and Mental Health)
One of the most important topics for which psychologists use animal experimentation is the study of interactive effects of genes and the environment on the development of the brain and subsequent behavior. These studies can be done only if animals are used as subjects because they require subjects with a relatively short life span that develop quickly, invasive procedures to measure cell and brain activity, or the manipulation of major social and environmental variables in the life of the subject.
In the 1920’s, Edward C. Tolman and Robert Tryon began a study of the inheritance of intelligence using rats. They trained rats to run a complex maze and then, over many generations, bred the fastest learners with one another and the slowest learners with one another. From the beginning, offspring of the bright rats were substantially faster than offspring of the dull rats. After only seven generations, there was no overlap between the two sets, showing that intelligence is at least partly genetic and can be bred into or out of animals just as size, coat color, or milk yield can be.
Subsequent work with selectively bred bright versus dull rats, however, found that the bright rats would outperform the dull rats only when tested on the original maze used with their parents and grandparents; if given a different task to measure their intelligence, the bright rats were no brighter than the dull rats. These studies were the...
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Brain Studies (Psychology and Mental Health)
Another series of experiments that illustrate the role of animal models in the study of brain and behavior is that developed by David Hubel and Torsten Wiesel, who study visual perception (mostly using cats). Hubel and Wiesel were able to study the activity of individual cells in the living brain. By inserting a microelectrode into a brain cell of an immobilized animal and flashing visual stimuli in the animal’s visual field, they could record when the cell responded to a stimulus and when it did not.
Over the years, scientists have used this method to map the activities of cells in several layers of the visual cortex, the part of the brain that processes visual information. They have also studied the development of cells and the cell connections, showing how early experience can have a permanent effect on the development of the visual cortex. Subsequent research has demonstrated that the environment has major effects on the development of other areas of the brain as well. The phrase “use it or lose it” has some accuracy when it comes to development and maintenance of brain connections and mental abilities.
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Harlow’s Experiments (Psychology and Mental Health)
Perhaps the most famous psychological experiments on animals were those done by Harry Harlow in the 1950’s. Harlow was studying rhesus monkeys and breeding them in his own laboratory. Initially, he would separate infant monkeys from their mothers. Later, he discovered that, in spite of receiving adequate medical care and nutrition, these infants exhibited severe behavioral symptoms: They would sit in a corner and rock, mutilate themselves, and scream in fright at the approach of an experimenter, a mechanical toy, or another monkey. As adolescents, they were antisocial. As adults, they were psychologically ill-equipped to deal with social interactions: Male monkeys were sexually aggressive, and female monkeys appeared to have no emotional attachment to their own babies. Harlow decided to study this phenomenon (labeled “maternal deprivation syndrome”) because he thought it might help to explain the stunted growth, low life expectancy, and behavioral symptoms of institutionalized infants which had been documented earlier by René Spitz.
Results of the Harlow experiments profoundly changed the way psychologists think about love, parenting, and mental health. Harlow and his colleagues found that the so-called mothering instinct is not very instinctive at all but rather is learned through social interactions during infancy and adolescence. They also found that an infant’s attachment to its mother is based not on its...
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Limitations and Ethical Concerns (Psychology and Mental Health)
However, there are drawbacks to using animals as experimental subjects. Most important are the clear biological and psychological differences between humans and nonhuman animals; results from a study using nonhuman animals simply may not apply to humans. In addition, animal subjects cannot communicate directly with researchers; they are unable to express their feelings, motivations, thoughts, and reasons for their behavior. If a psychologist must use an animal instead of a human subject for ethical or practical reasons, the scientist will want to choose an animal that is similar to humans in the particular behavior being studied.
For the same reasons that animals are useful in studying psychological processes, however, people have questioned the moral justification for such use. Because it is now realized that vertebrate animals can feel physical pain and that many of them have thoughts and emotions as well, animal experimentation has become politically controversial.
Psychologists generally support the use of animals in research. The American Psychological Association (APA) identifies animal research as an important contributor to psychological knowledge. The majority of individual psychologists would tend to agree. In 1996, S. Plous surveyed nearly four thousand psychologists and found that fully 80 percent either approved of or strongly approved of the use of animals in psychological research....
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Regulations (Psychology and Mental Health)
In response to such concerns regarding the use of animals in experiments, the U.S. Congress amended the Animal Welfare Act in 1985 so that it would cover laboratory animals as well as pets. (Rats, mice, birds, and farm animals are specifically excluded.) Although these regulations do not state specifically what experimental procedures may or may not be performed on laboratory animals, they do set standards for humane housing, feeding, and transportation. Later amendments were added in 1991 in an effort to protect the psychological well-being of nonhuman primates.
In addition, the Animal Welfare Act requires that all research on warm-blooded animals (except those specifically excluded) be approved by a committee before it can be carried out. Each committee (known as Institutional Animal Care and Use Committees, or IACUCs) is composed of at least five members and must include an animal researcher; a veterinarian; someone with an area of expertise in a nonresearch area, such as a teacher, lawyer, or member of the clergy; and someone who is unaffiliated with the institution where the experimentation is being done and who can speak for the local community. In this way, those scientists who do animal experiments must justify the appropriateness of their use of animals as research subjects.
The APA has its own set of ethical guidelines for psychologists conducting experiments with animals. The APA guidelines are intended for use...
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Sources for Further Study (Psychology and Mental Health)
American Psychological Association. Committee on Animal Research and Ethics. http://www.apa.org/science/animal2.html. Excellent and informative page clearly describing the value of animal research to psychology and the ethical and legal restrictions of its use, and providing links to full-text guidelines.
Cuthill, I. C. “Ethical Regulation and Animal Science: Why Animal Behavior Is Not So Special.” Animal Behaviour 72 (2007): 15-22. Good summary of the guiding principles of animal research legislation, refinement, replacement, and reduction.
Fox, Michael Allen. The Case for Animal Experimentation. Berkeley: University of California Press, 1986. Although the author is philosophically in favor of most animal experimentation, he gives a clear and thorough discussion of the entire context of animal experimentation from both sides. Includes sections on animal rights, similarities and differences between human and nonhuman subjects, the role of methodological considerations and replicability in scientific progress, and alternatives to animal testing. The author specifically addresses some of the uglier behavioral studies on animals, including some by Harry Harlow.
Gross, Charles G., and H. Philip Zeigler, eds. Motivation. Vol. 2 in Readings in Physiological Psychology. New York: Harper & Row, 1969. Although there are dozens of newer collections of articles in the...
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Animal Experimentation (Encyclopedia of Psychology)
The use of destructive and nondestructive testing upon various animal species in order to better understand the mechanisms of human and animal behaviors, emotions, and thought processes.
Biologists believe that chimpanzees share at least 98.4 percent of the same DNA as humans. Gorillas have a genetic composition which is at least 97 percent consistent with that of humans. Because the advancement of scientific technology has increasingly demonstrated similarities between animals and people, popular attitudes toward the use of animals in research and scientific experimentation have changed considerably. Ironically, this knowledge of the close genetic bond between species has enhanced the interest in animal experimentation. Nevertheless, 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 stressll of which animals are capable of experiencing.
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