Comparative Psychology: Definition, Examples, and Research

Comparative psychology is a branch of psychology that involves studying the behavior of animals and comparing it to that of humans. Researchers look at how behavior is organized in non-human animals, including insects, birds, fish, primates, rats, and dolphins, to explore developmental, cognitive, and evolutionary patterns across species.

By using comparative methods of study, researchers are able to better understand evolutionary relationships. Comparative methods allow scientists to examine the similarities and differences between various species and consider how these compare to human beings.

For example, comparative psychology might look at how the emotional bonds in animals like birds and primates are similar to the development of attachment patterns in humans.

The field is rooted in the work of Charles Darwin and other researchers and now incorporates multiple disciplines, including psychology, genetics, ecology, biology, and anthropology. It is also sometimes referred to as animal psychology.

Definition of Comparative Psychology

“Comparative psychology, in its narrow meaning, refers to the study of the similarities and differences in the psychology and behavior of different species,” explain researchers Raffaele d’Isa and Charles I. Abramson in an article published in Frontiers in Psychology.

History of Comparative Psychology

Comparative psychology has been described as one of the oldest organized social sciences, with written mentions first appearing as early as 1808. The field became more prominent after Darwin’s On the Origin of the Species was published in 1859.

Darwin’s pioneering theories were based on his observations of animal species. His work introduced natural selection, the process by which animals that are better adapted to their environments are more likely to survive, reproduce, and pass down those advantageous characteristics.

In 1864, the first book titled Comparative Psychology (in French as Psychologie Comparée) was published. George Romanes later referred to the term in his 1882 book Animal Intelligence, which focused on comparing animals and humans (Abramson, 2023). 

The psychologist Alfred Binet, developer of the world’s first intelligence test, was also interested in the topic. The Association for the Study of Comparative Psychology was founded in 1885, seven years before the American Psychological Association was established (Abramson, 2023).

Other notable figures in this field include Konrad Lorenz, C. Lloyd Morgan, and Harry Harlow. 

• Lorenz is known for his famous research on imprinting, which demonstrated that there is a critical developmental period for the formation of attachment relationships. 
• Morgan is often known as the “father of comparative psychology” because he created guidelines for using psychological interpretations of animal behavior. He also introduced the principle known as Morgan’s canon, which stresses that researchers should not anthropomorphize animals. This means they should not ascribe human attributes, emotions, or motivations to animals if their behaviors can be described more simply (Karin-D’Arcy, 2005).
• Harlow’s experiments with rhesus monkeys established the importance of love and care for healthy development.

The work of behavioral psychologists also influenced the development of comparative psychology, particularly in the work and insights of Russian physiologist Ivan Pavlov. Pavlov’s experiments with dogs led to his realization that a neutral stimulus could come to produce a learned behavior if it is first associated with an unconditioned stimulus that naturally and automatically produces a response. This process is known as classical conditioning (aka respondent conditioning) and can be applied to human learning as well. 

Other behavioral psychologists, including Watson and Skinner, emphasized the importance of observable behaviors in understanding human learning (they are also known for their research with animals).

Why Study Animal Behavior?

Studying non-human behavior can have several important benefits. By looking at the behaviors of other living organisms, researchers can create comparisons that can help them better understand where these behaviors are from and how they function.

• It can help us better understand human behavior. By studying animals and other living organisms, researchers are able to get a better look at the evolutionary and biological basis for human behavior.
• It helps us better understand the evolutionary process. Many animals engage in behaviors that are similar to human behavior (and vice versa). Looking at this similarities and differences can help us see how things like cooperation, aggression, and other traits evolved to aid in human survival.
• It can offer other insights into specific areas like social behavior, learning, cognition, and environmental influences.

Studying animals also gives us a better appreciation of non-human organisms. This can play an important role in animal welfare and conservation efforts.

Experts suggest that looking at research findings in the field of comparative psychology allows psychologists to develop new ways to address psychological disorders in humans, including depression, substance use, and social communication disorders (Marston & Maple, 2016)

What Do Comparative Psychologists Study?

Comparative psychologists explore a wide range of topics, including:

• Animal communication: Studying how animals communicate can give insights into how language evolves and how it compares to human communication.
• Social behavior: Researchers are interested in understanding social dynamics, hierarchies, dominance, prosocial behaviors, reproduction, and altruism.
• Cognition and intelligence: Comparative psychologists also look at the cognitive abilities of non-human organisms to examine evolutionary differences.
• Emotions: Studying emotions like fear, attachment, and anger can give researchers more insights into how such emotions may influence human behavior.
• Learning: Examining how animals learn can offer information about cognitive processes, which may be helpful in understanding how people acquire and use information.

Examples of Comparative Psychology Research

Lorenz’s Imprinting Experiments

Comparative psychology has also offered insights into developmental stages and processes that are also important in human beings. Zoologist Konrad Lorenz demonstrated that attachment to a caregiver needs to occur during a critical point in development (Kaba, 2009).

In his research, he found that ducks and geese attach to a parental figure during a critical point in development. Famously, Lorenz was able to get the animals to attach to him. (You’ve probably even encountered images of him being followed by the ducks and geese who had imprinted on him, much like baby ducklings follow their mother).

Harlow’s Monkey Experiments 

Harlow’s experiments revealed more insights into the importance of attachment and the factors that influence it. He separated infant monkeys from their mothers and offered them a choice between a wire “mother” that provided food and a “cloth” mother that provided comfort. The results demonstrated that the care and comfort offered by the soft, cloth mother was what the baby monkeys would mainly seek.

His work also showed that depriving baby monkeys of nurturing attachments and social relationships led to severe developmental disturbances (van Rosmalen, der Veer, & van der Horst, 2020).

Pepperberg’s Research with Alex the Parrot

Researcher Irene Pepperberg’s famous research with the gray parrot named Alex had a significant impact on our understanding of the language and cognitive capabilities of other species. Through her research, she was able to show that Alex was able to understand concepts such as colors, numbers, shapes, and analogies. He had a vocabulary of around 150 words (Boyle, 2018).

Conclusion

Comparative psychology plays an important role and can help researchers develop important insights about people and animals. While animals and humans are similar in many ways, it’s important to remember that they are not the same. Research in this field is also not without controversy. Harlow’s experiments, for example, have been widely criticized for their shocking cruelty. Today, other critics emphasize that experimenting on animals raises serious ethical issues.

Sources:

Audubon. How Irene Pepperberg revolutionized our understanding of bird intelligence.

d’Isa, R., & Abramson, C. I. (2023). The origin of the phrase comparative psychology: an historical overview. Frontiers in Psychology, 14, 1174115. https://doi.org/10.3389/fpsyg.2023.1174115

Karin-D’Arcy, M. R. (2005). The modern role of Morgan’s Canon in comparative psychology. International Journal of Comparative Psychology, 18(3). https://doi.org/10.46867/IJCP.2005.18.03.06

Marston, D. C., & Maple, T. L. (2016). Comparative psychology for clinical psychologists and therapists: What animal behavior can tell us about human psychology. Jessica Kingsley Publishers.

Schneirla, T. C. (1966). Behavioral development and comparative psychology. The Quarterly Review of Biology, 41(3), 283–302. https://doi.org/10.1086/405056

van Rosmalen, L., van der Veer, R., & van der Horst, F. C. (2020). The nature of love: Harlow, Bowlby and Bettelheim on affectionless mothers. History of psychiatry, 31(2), 227–231. https://doi.org/10.1177/0957154X19898997