What type of research are psychologists who watch the behavior of chimpanzee societies using?

Harry Harlow’s empirical work with primates is now considered a “classic” in behavioral science, revolutionizing our understanding of the role that social relationships play in early development. In the 1950s and 60s, psychological research in the United States was dominated by behaviorists and psychoanalysts, who supported the view that babies became attached to their mothers because they provided food. Harlow and other social and cognitive psychologists argued that this perspective overlooked the importance of comfort, companionship, and love in promoting healthy development.

Using methods of isolation and maternal deprivation, Harlow showed the impact of contact comfort on primate development. Infant rhesus monkeys were taken away from their mothers and raised in a laboratory setting, with some infants placed in separate cages away from peers. In social isolation, the monkeys showed disturbed behavior, staring blankly, circling their cages, and engaging in self-mutilation. When the isolated infants were re-introduced to the group, they were unsure of how to interact — many stayed separate from the group, and some even died after refusing to eat.

Even without complete isolation, the infant monkeys raised without mothers developed social deficits, showing reclusive tendencies and clinging to their cloth diapers. Harlow was interested in the infants’ attachment to the cloth diapers, speculating that the soft material may simulate the comfort provided by a mother’s touch. Based on this observation, Harlow designed his now-famous surrogate mother experiment.

In this study, Harlow took infant monkeys from their biological mothers and gave them two inanimate surrogate mothers: one was a simple construction of wire and wood, and the second was covered in foam rubber and soft terry cloth. The infants were assigned to one of two conditions. In the first, the wire mother had a milk bottle and the cloth mother did not; in the second, the cloth mother had the food while the wire mother had none.

In both conditions, Harlow found that the infant monkeys spent significantly more time with the terry cloth mother than they did with the wire mother. When only the wire mother had food, the babies came to the wire mother to feed and immediately returned to cling to the cloth surrogate.

Harlow’s work showed that infants also turned to inanimate surrogate mothers for comfort when they were faced with new and scary situations. When placed in a novel environment with a surrogate mother, infant monkeys would explore the area, run back to the surrogate mother when startled, and then venture out to explore again. Without a surrogate mother, the infants were paralyzed with fear, huddled in a ball sucking their thumbs. If an alarming noise-making toy was placed in the cage, an infant with a surrogate mother present would explore and attack the toy; without a surrogate mother, the infant would cower in fear.

Together, these studies produced groundbreaking empirical evidence for the primacy of the parent-child attachment relationship and the importance of maternal touch in infant development. More than 70 years later, Harlow’s discoveries continue to inform the scientific understanding of the fundamental building blocks of human behavior.

References

Harlow H. F., Dodsworth R. O., & Harlow M. K. (1965). Total social isolation in monkeys. Proceedings of the National Academy of Sciences of the United States of America. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC285801/pdf/pnas00159-0105.pdf

Suomi, S. J., & Leroy, H. A. (1982). In memoriam: Harry F. Harlow (1905–1981). American Journal of Primatology, 2, 319–342. doi:10.1002/ajp.1350020402

Tavris, C. A. (2014). Teaching contentious classics. The Association for Psychological Science. Retrieved from https://www.psychologicalscience.org/observer/teaching-contentious-classics

Undergraduates sometimes ask what the value of animal research is in psychology. The study of nonhuman animals has actually played a huge role in psychology, and it continues to do so today. If you’ve taken an introductory psychology class, then you have probably read about seminal psychological research that was done with animals: Skinner’s rats, Pavlov’s dogs, Harlow’s monkeys. Unfortunately, many introductory textbooks don’t give the full picture of animal research. Studies are often described without specifying that they were animal studies. When human studies are presented, there is rarely discussion of the basic animal research that enabled those studies to be done. Finally, information regarding the ethical and regulatory environments in which animal research is conducted is covered in a superficial manner or omitted altogether. These are important issues that deserve better understanding and broader discussion.

Why Nonhuman Animals are Studied in Psychology

Part of the justification for why nonhuman animals are studied in psychology has to do with the fact of evolution. Humans share common ancestry with the species most commonly studied in psychology: mice, rats, monkeys. To be sure, each species has its own specializations that enable it to fit into its unique ecological niche; but common ancestry results in structural (e.g., brain) and functional (e.g., memory) processes that are remarkably similar between humans and nonhumans. In addition, we can better understand fundamental processes because of the precise control enabled by animal research (e.g., living environments, experimental conditions, etc.). We can also ask and answer certain questions that would be difficult or impossible to do with humans. For example, we know what the connections are between the amygdala and other brain regions, but how does activity in the amygdala affect brain functioning? Using a new technique, it is now possible to temporarily inactivate the amygdala in a monkey and see how other brain areas (including those that are not directly connected to the amygdala) change their activity (Grayson et al., 2016). A study such as this not only helps us better understand how the brain works, but it also has enormous potential for developing treatments for people who have abnormal patterns of brain activity, such as those with epilepsy or Parkinson’s disease. Ten years from now, students may very well read in their textbooks about a “new treatment” to help people with Parkinson’s disease. Will this monkey study, which enabled such a discovery to be made, be described? Probably not, in much the same way that nonhuman research that permitted a significant human study to be conducted is rarely described in today’s textbooks.

Weighing Harm and Benefit

Researchers who study nonhumans recognize that their studies may involve certain harms that can range from the relatively minor (e.g., drawing a blood sample) to the more serious (e.g., neurosurgery). The research community tries to mitigate some of the harms by insuring, for example, that the animals’ psychological well-being is optimized; in fact, there is a large body of psychological research that focuses on animal welfare and identifying best practices to house and care for animals in captivity. Still, some harms will remain, and ethically, one must weigh those harms against the potential benefits (for humans and for the animals themselves) to be obtained from the research. Equally important is the consideration of the potential harms to humans of not doing the research. For example, without any animal research, effective treatments for human conditions like Alzheimer’s disease may very well be found, but it would certainly take decades longer to find them, and in the meantime, millions and millions of additional people would suffer.

Regulations for Animal Research

Finally, it’s important to note that animal research in the United States is very tightly regulated by a series of federal and state laws, policies and regulations, dating back to the landmark Animal Welfare Act from 1966. Oversight and inspection of facilities is provided by the U.S. Dept. of Agriculture, and, at the local level by Institutional Animal Care and Use Committees (IACUCs). Even procedures as simple as drawing a blood sample or testing an animal on a cognitive task must be approved by the local IACUC before the work can begin. Part of that approval process requires the scientist to identify whether there might be less invasive ways to do the same thing. In addition, the scientist must justify the numbers of animals that they use, insuring they are using the smallest number possible.

Animal research continues to play a vital role in psychology, enabling discoveries of basic psychological and physiological processes that are important for living healthy lives. You can learn more about some of this research, as well as the ethical and regulatory issues that are involved, by consulting online resources such as Speaking of Research. 

References

Grayson D.S., Bliss-Moreau E., Machado C.J., Bennett J., Shen K., Grant K.A., Fair D.A., Amaral, D.G. The rhesus monkey connectome predicts disrupted functional networks resulting from pharmacogenetic inactivation of the amygdala. Neuron. 2016 Jul 20;91(2):453-66. 

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