Descartes

Humans’ fascination with animal behavior and cognition likely dates back as far as our fascination about our own behavior and mental processes. For the sake of brevity, we begin our historical journey in the 16th century with the Scientific Revolution. During this era of major scientific advancement, philosophers of the 16th and 17th centuries began studying animal behavior in a more systematic way than previous generations. Many of their questions focused on anatomy and structure with the ultimate goal of better understanding the human body. For example, physician William Harvey (1578–1657) experimented on the circulatory systems of both warm- and cold-blooded animals in order to “illustrate man by the structure of animals” (Power, 1898).

René Descartes (1596–1650) was one of Harvey’s contemporaries who also compared human and animal behavior, cognition, and anatomy. Inspiration struck one day while Descartes was visiting a royal garden. At the time, a new fad for the French elite were water gardens containing automata, hydro-powered lifelike machines. The moving metal creatures became Descartes’ muse, and he returned home to create one of the most well-known theories in modern philosophy. Descartes conceptualized the body to be like a machine; when stimulation was applied to the body, such as a child touching a candle flame, the brain responded by releasing animal spirits. This fluid traveled down channels, similar to the pipes inside the automata, and caused an involuntary reflexive movement of the hand away from the flame. No thoughts or fancy mental power is involved, just a basic reflexive motion system.

Due to the strong infusion of Christianity into the Western culture at the time, including science and philosophy, Descartes drew a hard line in the sand between humans and animals. Though both had machinelike bodies that were governed by animal spirits, God had gifted humans with a soul (i.e., mind). This metaphysical soul within a machine body was the foundation for Descartes’ iconic mind–body dualism perspective. This soul was located deep in the brain and controlled the rest of the body. Among other abilities, Descartes thought the soul allowed humans to reason; engage in voluntary, nonreflexive behaviors; use language to communicate; and think mathematically and abstractly. As we will discover, animal cognition research has contradicted the uniqueness of many of these abilities, but at the time there was no clear indication that animals were more than reflexive, unfeeling automata. Descartes’ stance, backed up by the Christian belief of human superiority and dominion over animals, laid the foundation of how society and science came to view and treat animals for more than two centuries.

Before we get too far, a bit of a public service announcement is in order. When evaluating historical events and actions, it’s important to consider the historical context within which they occurred. For example, vivisection, the act of performing invasive experimental surgeries on a live animal, was popular and accepted among physicians like William Harvey. While this may seem inhumane or barbaric by today’s standards, the widespread understanding during Harvey’s time was that animals were basically just machines, lacking both feeling and emotions. Knowing this, is it fair to judge someone for vivisecting in 1650 using today’s standards? Probably not, especially given everything we learned about the human body from their work. Armed with a more informed understanding of the knowledge and values of Harvey’s time, we can look back at his experiments and appreciate them for what they contributed to science—even if we do not condone them.

There are, of course, always exceptions. While the viewing of animals as machines and the practice of vivisection were common in the 16th to 19th centuries, some held strong dissenting opinions. Philosopher and animal advocate Voltaire (1694–1778) accused his medical contemporaries of hypocrisy, saying:

This excerpt from Voltaire’s “beasts” entry in his Dictionnaire Philosophique was published nearly a century before arguably the most influential book in animal cognition’s history by Charles Darwin, On the Origin of Species. Yet, in Voltaire’s writings, we already see inklings of what was to come. Voltaire and others poked holes in Descartes’ line in the sand: If animals are similar enough to humans to allow for anatomical and physiological comparison, similarities between humans and nonhumans may not end with the physical body. If only Voltaire had been born a century later, he would have lived to see the first major shift toward an acknowledgment of animal minds.

Darwin’s Continuity of Species

At the time of its publication in 1859, On the Origin of Species stirred international controversy, and understandably so. Armed with thousands of compelling observations, Charles Darwin (1809–1882) proposed nature had not been created in its current form by God, as society and even science at that time believed (Gould, 2002). Instead, the many species Darwin had observed seemed to better fit within a theory that they were the product of evolution over time in response to changes in their environment and competition for resources. As prominent zoologist Stephen J. Gould (2002) wrote, Darwin wanted society to stop viewing nature as some beautiful, majestic harmony and instead to see it as a “struggle for personal success” (p. 121), with animals and plants savagely competing with each other to survive and pass on their genes to the next generation. As if this was not enough, Darwin (1871) later published The Descent of Man and Selection in Relation to Sex, which made the mind-blowing conclusion that millions of years ago, humans shared a common ancestor with the other great apes. By kicking humans off their pedestal and inserting them into the animal kingdom, Darwin boldly redefined the centuries-old relationship between humans and animals—and made a lot of people really mad in the process. While these ideas were accepted among some academics at the time, as you might imagine, they were largely received as serious threats to Western Christian ideology.

Along with noticing a clear continuity of species with respect to similar anatomy and physiology among humans and animals, Darwin also noted continuity for psychological processes as well (e.g., emotions, concept formation, complex communication; Boakes, 1984). His The Expression of the Emotions in Man and Animal, for example, opened the door to thinking more seriously about the hypocrisy raised by Voltaire a century earlier. In one chapter, Darwin (1872) identified behavioral, vocal, and physiological similarities in how basic emotions such as terror, pain, and joy are experienced by both humans and animals. Using systematic (i.e., structured, organized) observations as evidence to support his theories, Darwin encouraged an entirely new way of viewing animals—one that cemented an interest in investigating animals’ subjective experiences and their cognitive abilities.

Naturalists and Psychologists

Inspired by Darwin’s findings, naturalists and early psychologists became increasingly curious about looking for parallels between humans’ and animals’ cognitive abilities. As the name might imply, naturalists are interested in observing the natural world, without intervention or experimentation. It is from naturalists that we come to understand the natural history of a species. Natural history includes observations of an animal’s social, reproductive, habitational, morphological (i.e., how they look physically), cognitive, and foraging characteristics, as well as other features of that species in the wild. Darwin was a naturalist; we know this because he spent decades observing, recording, and sampling in order to develop his theory of how organisms change over time. By studying features of finches’ natural history, for example, he was able to solve the mystery of their differently sized beaks—where you live dictates what’s on the menu (e.g., seeds vs. nuts), and what’s on the menu drives the evolutionary refinement of your food extraction tool (e.g., pointy vs. blunt beak).

Once word spread that animals might also have subjective experiences and cognitive abilities, many of the naturalists of Darwin’s time set out to investigate his claims. One famous naturalist and friend of Darwin’s was George Romanes (1848–1894). In his book Animal Intelligence, Romanes (1882) reported dozens of stories of complex cognitive behaviors in everything from scorpions to elephants. In those stories, he tended to overascribe human traits to animals, such as his account of scorpions choosing to commit suicide rather than burning in a fire or foxes vindictively getting back at their fox friends for failing a hunting expedition. This sort of 1:1 comparison of animals to humans, while a well-intentioned effort to “raise the brutes and lower the humans,” as the trend was called, has many drawbacks that did not go unnoticed by his contemporaries.

While British naturalists laid the foundation in the late 19th century by reporting natural observations and stories about animals, American psychologists at the beginning of the 20th century drew conclusions about animals’ cognitive abilities by turning to the laboratory. At the time, psychology was locked in a bitter dispute about the direction the field should take. Some, like Edward Titchener (1867–1927), argued for more subjective methods, such as introspection, to better understand the human mind. Introspection was a technique made popular by a psychology school of thought called structuralism. As its name implies, structuralists like Titchener were curious about the structure of the mind, that is, how is the mind organized, how does it process information, and so on. For example, Titchener might present rose oil to a research participant and ask them how it makes them feel or what they think about when they smell it. While it might seem like a good idea, introspection’s subjectivity made it difficult to learn anything concrete about the mind, which frustrated psychologists like John Watson (1878–1958), who was tired of the subjectivity and lack of rigor his colleagues were using to study the human mind. In what is known by many as his Behaviorist Manifesto, Watson (1913) heavily criticized his fellow psychologists, calling for an end to studying any behavior that could not be outwardly observed and measured—including the mind. By avoiding studying something as abstract and unobservable as the mind, Watson thought psychology could join the ranks of sciences like biology and chemistry.

At this point, you might be asking, “How could a psychologist demanding that psychology not study mental processes contribute to a field that is all about studying animals’ mental processes?” Well, it was not Watson’s bitter rejection of psychology’s “soft science” direction that mattered. Rather, the school of thought Watson created to replace structuralism, called behaviorism, established a new lens through which American psychologists would study cognitive abilities in humans and animals. For better or worse, behaviorism had a lasting effect on the field of animal cognition.

Along with Watson’s appreciation (though not complete agreement; Logue, 1978) of Darwin’s continuity of species argument, his call for greater objectivity and scientific rigor inspired the establishment of more and more animal learning and behavior laboratories across the United States. In these laboratories, psychologists avoided using people’s animal stories as evidence, favoring instead to run formal experiments. Some researchers performed studies to gain a better understanding of an animal’s subjective experience by providing different visual stimuli, for example, and measuring its reaction. This is how we learned that bees can see in color, for example. Other researchers manipulated features of the animal’s environment or physiological state (e.g., restrict food to make the animal hungry) and recorded differences in the animal’s behavior. Those differences in outward behavior, they argued, were observable evidence of what was going on inside the animal. For example, Tolman (1948) famously tested hungry rats in mazes where there was either food or no food at the end of the maze. As he predicted, the rats who had food waiting for them zipped through the maze faster and made fewer errors than the rats who were not rewarded for completing the maze. Curious whether the unrewarded rats had “learned less” than their rewarded counterparts, Tolman put some food at the end of the maze and sent the unrewarded group through. To his surprise, the unrewarded rats had not learned less; they just were not motivated to show him what they knew. Immediately after finding food at the center, the unrewarded rats started sprinting through the maze. The moral of the story here was an important one: An organism’s outward behavior does not always tell the whole story. By figuring out ways to manipulate the animal’s unobservable internal state, behaviorists were able to make inferences about animals’ cognition and subjective experiences.

The results obtained by psychologists like Tolman and Watson could not have been obtained by naturalists because of the strict procedures they used. Similarly, the realness of the naturalists’ observations could not have been obtained by the sterile, artificial environments created in the laboratory by psychologists. In this way, two very different sets of approaches offered valuable insights moving toward one unified field.

Charles Henry Turner

After graduating valedictorian of his high school class, Charles Henry Turner (1867–1923) went on to college, where he published his first paper at just 24 years old (Turner, 1891). When a shorter version of that three-part paper appeared in Science (Turner, 1892a), Turner became one of, if not the first, African Americans to be published in this highly prestigious journal (Abramson, 2006). As another first, Turner was the first African American to earn a graduate degree from the University of Cincinnati in 1892. That same year he produced three other publications on the diverse topics of grapevine leaf growth (Turner, 1892b), aquatic crustaceans (Turner, 1892c), and variations in spiderweb formation (Turner, 1892d).

Not satisfied with a master’s degree, he made history again studying zoology and became the first African American to earn a PhD from the University of Chicago. Even with a PhD from the school and dozens of publications, when Turner applied for a professorship at his alma mater, he was rejected. Whether his subsequent decision to teach at the high school level was forced or a preferred choice is unknown. Some (e.g., Abramson, 2009) speculate that despite earning the admiration and respect of white colleagues in the laboratory, institutional racism at the administrative level kept him from achieving his goal of a permanent professorship. Given Turner’s tremendous publication record—more than double that of many of his white male colleagues’ (Scarborough & Furumoto, 1987)—the fact he was passed up indicates race was very likely a significant factor.

Undeterred, Turner set up a productive research laboratory at Sumner High School, an all African American school. He lived, breathed, and worked animal cognition—going so far as to name one of his sons Darwin Romanes Turner. As a high school teacher, much of Turner’s work focused on insects, including spatial navigation in ants and sensory systems in honey bees and moths. As Abramson (2006) points out, Turner’s productivity was even more astonishing given the many barriers he faced as a high school teacher, including “few formal laboratory facilities, no easy access to research libraries, no opportunity to train research students at the undergraduate or graduate level, heavy teaching loads, low pay, and restricted research time” (p. 42). Facing these challenges, Turner persevered, contributing information about the behavior of dozens of different species to the scientific literature. In some cases, Turner pioneered methodologies and techniques that are still used—and sometimes misattributed to his more well-known white contemporaries (Abramson, 2003, 2006).

Though Turner used the laboratory-based method made popular by behaviorists at the time, his language and interpretations of behavioral findings reflected a researcher who was willing to make inferences about the minds of his subjects. For example, in his discussion of cockroaches running mazes, Turner (1913) wrote, “Some few roaches, after making several attempts to find an exit from the maze, stop trying and act as though they have given up all hope of succeeding” (p. 355). When he observed a cockroach rush to the edge of the maze and pause prior to jumping off, he concluded, “At times the roach acts as though experiencing the emotion psychologists call will” (p. 361). While Turner was willing to discuss animals’ mental processes like “giving up” and voluntary decision making, he balanced it with the kind of laboratory objectivity that was championed by the behaviorist movement of his time.

Not betraying his naturalist roots, other lines of Turner’s research were more observational in their methods. In one study, he removed the queen wasp from a small nest of 9 pupae and 15 larvae in order to learn how never seeing an adult in the colony affected subsequent generations’ behavior (Turner, 1912). Among other discoveries, this 6-week-long detailed behavioral study allowed him to conclude that proper construction of a wasp nest may not be an entirely instinct-driven process.

In addition to contributing internationally renowned research during a time of blatant racism, Turner was also committed to the issue of education for African American youth. In one publication, for example, he defends the importance of teaching biology in African American schools as a way to “win the respect of other races” (Turner, 1897, p. 2). For his sustained civil rights work, at least four predominantly African American–serving institutions today bear his name. Sadly, Turner’s prolific research program at Sumner High School lasted only 15 years, and he died shortly after retiring in 1922, but his name and legacy live on. The Animal Behavior Society has furthered Turner’s advocacy work by offering the Charles H. Turner Award, a conference attendance scholarship for underrepresented college students interested in animal behavior, and Turner is the focus of the 1997 children’s book Bug Watching With Charles Henry Turner, which introduces the next generation of scientists to animal behavior.

Margaret Floy Washburn

Like Turner, Margaret Floy Washburn (1871–1939) also set herself apart from her peers from an early age, first by starting college at the age of 16. During her senior year of college, Washburn turned her attention to pursuing psychology, where, also like Turner, she faced discrimination. Because Washburn was a woman, she could not attend her preferred graduate program at Columbia University. Instead, she was allowed only to audit courses and work in an experimental psychology laboratory (McHenry, 1980). Washburn was lucky in that she considered her research adviser, James McKeen Cattell, to be “a lifelong champion of freedom and equality of opportunity” (O’Connell & Russo, 1983, p. 17), but when even he could not get her into Columbia, she moved on to Cornell University, where she became the first woman ever to be awarded a PhD in psychology. Her human psychology research focused on the relationship between visual imagery, movement, and perception. Her publications included topics like distance judgments (Washburn, 1894), object recognition (Washburn, 1897), logic (Washburn, 1898), and preferences for color combinations (Washburn, MacDonald, & Van Alstyne, 1922), to name a few.

Eventually, however, Washburn grew dissatisfied with the extremes of structuralism (all mental) and behaviorism (all outward behavior) and decided to develop her own dualist theory regarding the connection between motor movement and social consciousness (i.e., awareness). Specifically, she hypothesized that development of social consciousness did not arise in social species from imitation learning, but rather that our physical social behaviors during early childhood actually allow social consciousness to develop (Washburn, 1903). As you might suspect, Washburn’s controversial body-informing-mind theory would have made Descartes roll in his grave! We encourage the reader to consult Martin (1940) for a fantastic synthesis of Washburn’s major contributions.

Washburn settled at Vassar College, where, with the assistance of senior psychology students working in her laboratory, she published more than 70 articles in the American Journal of Psychology. Due to her gender, Washburn’s climb to the top of the ranks as a pioneering experimental psychologist was not a smooth one. Her strategy was to essentially ignore the established social norms of how women scientists, and women in general, were supposed to behave around men. Vassar College’s president during Washburn’s tenure recounted, “Miss Washburn had been intrepid enough to invade the sacred precinct of the men’s smoker at psychological meetings. Marching uninvited into its midst, she had sat down and lighted a cigar. None questioned her privilege to enjoy the smoker thereafter” (MacCracken, 1950, p. 70). Naturally, only someone this brazen could take the reins and pull together years of research to write the first textbook for an entirely new field, and that’s just what Washburn did.

Anthropomorphism

Imagine (or perhaps recall an actual memory if this has ever happened to you) that you return home from work and your dog does not greet you excitedly at the door. Instead, she peeks around the corner at you, her tail between her legs, head down in a most submissive posture, avoiding eye contact. Something is definitely going on, but you cannot determine what. You enter the living room to find it absolutely destroyed—couch cushion stuffing, houseplants, potting soil, and shredded newspaper litter the floor. Now, how might you interpret your dog’s behavior? If you’re thinking guilt, remorse, embarrassment, or shame, you would not be alone. Do a quick Internet search for dog shaming memes if you do not believe us. Attributing human traits to a nonhuman entity, termed anthropomorphism, is rampant in how most people think about and interact with animals, whether they are pets or not (Horowitz & Bekoff, 2007). Some researchers even speculate that our tendency to see commonality between human and animal behavior could be the result of thousands of years of human evolution. Specifically, it may have been an advantage to our ancestors to better be able to (or perhaps think they were better able to) predict an animals’ behavior (e.g., Mithen, 1996).

The word anthropomorphism existed for a long time, mainly to describe gods and celestial beings as humanlike, but its likely first usage for animals was made in 1858. This was just around the time Darwin began promoting his ideas that would be published the following year in The Origin of Species. But it was not Darwin himself who used the term. Philosopher and physiologist George Henry Lewes used it in his cautionary warning against doing it. As we saw earlier, neither Darwin nor some of his followers like Romanes saw much of a problem with anthropomorphizing. They did so liberally and with their own justification. It is worth noting that even Romanes had a limit, admitting that in drawing inferences about insect behavior, there is a “progressive weakening” of the ability to find similarities between human and nonhuman behavior (p. 9).

When behaviorism cornered the market on psychology at the turn of the 20th century, Watson and others outright rejected the liberties early animal researchers had taken in extending Darwin’s continuity-of-species assumption to animals’ minds. In many ways, their strong rejection makes sense given Watson’s goal was to make psychology an objective science, which neither studied nor drew conclusions about anyone’s mental processes, human or nonhuman. While some at the time rebelled against Watson’s strict behaviorism, it was not until the 1950s or so that researchers “brought the mind back into experimental psychology” (Miller, 2003, p. 141). The trickle-down effect from human psychology to the animal cognition world was slow, but by the 1970s, studying animals’ cognitive abilities had regained traction and approval (Wynne, 2007). If you look carefully in this and subsequent chapters, you’ll find a gap in published animal cognition work from around 1940 to 1970. This reflects behaviorism’s stifling effect on the field.

Whether or not anthropomorphism has a place in animal cognition research depends on who you talk to. Some argue that anthropomorphism represents the “prescientific,” subjective way of thinking that experimental psychologists have tried to avoid engaging in (e.g., Wynne, 2007). Wynne makes a good point when he says that since Darwin’s time, we have uncovered many lawful and predictable relationships about animal behavior that do not require us to anthropomorphize anymore. For example, in the case of the hypothetical dog destroying my house, I could stop and remember back to 1 month ago when my dog tipped over a potted plant and I stood over him and loudly scolded him. Now, recalling that memory, the behavior I saw at the front door could be explained theoretically as a normal fear response, with my dog anticipating punishment for tipping over the potted plant. My interpretation no longer needs to connect how I would feel in that situation and arrive at guilt. Instead, we can use what we have learned about predictable relationships between the environment, behavior, and outcomes, in order to explain what I saw.

Another reason why interpretations grounded in anthropomorphism have been challenged is because they offer a convenient way to stop searching for answers by applying an easy label to behaviors that look familiar (e.g., Blumberg & Wasserman, 1995). According to this argument, once I identify a behavior that looks familiar enough for me to interpret it, such as how I would feel and behave if I got caught doing something wrong, I can stop investigating other possible explanations. Who knows, maybe my dog was behaving that way because she was actually sick from eating the plant she tipped over, but I was too busy posting photos of her on social media to notice. A label is just a label, not necessarily an actual explanation, but by anthropomorphizing my dog’s behavior, I can stop at the label of guilt and snap a funny photo.

But wait, what if my dog was experiencing guilt and I dismissed it because I channeled my inner John Watson and ignored it? Famed ethologist Konrad Lorenz (1991) said, “If we feel ourselves emotionally affected by the behavior of an animal, it is a clear indication that we have intuitively discovered a similarity between its behavior and human behavior. We should not conceal this in our description” (pp. 260–261). While we advocate for considering behavior theory interpretations first, we also neither ignore nor avoid investigating cognitive similarities between humans and nonhuman animals. If we did, our interpretations of animal behavior could unnecessarily over- or underestimate their actual abilities, just because we are afraid of drawing comparisons to human behavior.

The second half of the 20th century produced two other scientists whose views on anthropomorphism are also important to consider. Donald Griffin (1976) was one of the first who dared to suggest that scientists might actually benefit from an anthropomorphic lens of interpretation (Wynne, 2005). For example, given the experimental research that had already occurred, Griffin thought it was no longer accurate to insist that animals had no awareness of the world at all, and if that was the case, anthropomorphism with regard to awareness would be beneficial to future research. A decade later, Gordon Burghardt coined the term critical anthropomorphism for the use of data from multiple sources—including anthropomorphic ones—but which could then be formed into appropriately testable hypotheses (Burghardt, 1985). Research on reconciliation in chimpanzees (Pan troglodytes; de Waal, 1999) and self-recognition in a variety of species (Gallup, 1970), for example, are both areas of study in which discoveries might not have been possible without at least some degree of anthropomorphism (Burghardt, 1985).

Human Uniqueness

Underlying anthropomorphism is a fundamental belief in commonality, the assumption that there is something similar between humans and other animals. While it’s normal to anthropomorphize, it must be applied carefully because we cannot ask the dog, “Are you cowering because you feel ashamed about destroying my living room?” The argument by analogy forces animal cognition researchers to think more deeply about animal behavior.

See if you can identify the problem with the following:

In the first two statements, claims are made. Turkeys and humans are, indeed, both animals, and turkeys are considered food in the United States. The analogy breaks down at the conclusion. Just because turkeys and humans share some similar features, it does not mean that we can confidently extend those similarities to assume similarities across all possible areas.

Here is another set of statements that are more relevant to our discussion:

Darwin’s assumption of continuity of species was invaluable to science, but it requires a strong need for checks and balances in logic and conclusions. This means every good animal cognition researcher must toe the line of having an open mind and being a healthy skeptic. Inappropriate arguments by analogy can muddy the waters of interpretation when we observe animals’ outward behavior. It’s important to remember that just because an animal exhibits some outward behavior or possesses some brain structure that, in humans, corresponds to a particular mental state or cognitive ability, it does not mean we can jump to conclusions without serious consideration of alternative explanations. Further, each species has been acted upon by thousands, if not millions, of years of evolution, meaning assumptions should not be made about even the most familiar of behaviors. Try smiling at a baboon (Papio spp.) sometime, and when your friendly gesture is met with aggression (because, actually, smiling is a threat gesture in almost every nonhuman species), you’ll understand what we mean about making assumptions.

You’re likely reading this book because you’re genuinely interested in learning more about the cognitive abilities of other species. While you may be open minded to the possibility that animals can manufacture and use tools, reflect on their own knowledge, or have culture, many people are not. For some, the threat of not being “special” anymore—whatever that means!—is a difficult pill to swallow. By engaging in what primatologist Frans de Waal calls anthropodenial, some people completely shut out the possibility that animals are capable of demonstrating evidence of complex social and cognitive abilities. Anthropodenialist perspectives keep humans at the top of an imaginary hierarchy. This hierarchy justifies our treatment of animals in ways that we would never treat humans, deepening the line in the sand that Descartes and others drew hundreds of years ago. If we found out other species are more similar to us than we’d like to think, it might force serious changes in our society, which many people simply are not ready or willing to think about.

In considering the roots of the line in the sand, the “humans are special” bias, we must go back further than Descartes to explore a system that is foundational to many societies: religion. Specifically in Westerns countries, Christianity has played an undeniable role in why humans tend to create a species hierarchy with humans at the top and why, for many years, the common belief was that humans were fundamentally different from other species (Singer, 2002). Christianity certainly impacted Descartes’ views and was a source of fear for Darwin as he prepared to publish On the Origin of Species. Thus, even with scientific rigor imposed by methodology (Chapter 2) and careful interpretations of findings, animal cognition researchers must also be aware of deep-seated biases at the societal level that may lead others to reject their findings.

Things have gotten much better in the past 50 years or so. Many of the methodological challenges are still present, but the field has grown and refined itself into a reputable science. Researchers like Jane Goodall and Irene Pepperberg have captivated audiences with their investigations, and popular science books on animal cognition have become New York Times best sellers. Keeping in mind the influence that society and its values has on science, the field’s second century should be an exciting one!

Medical Models

Brain Models

Evaluating Animal Models

Animal models will not be going away anytime soon. However, there are many challenges to using them. Practically speaking, human brains function with greater complexity than those of other species (including other primates), which may make it difficult to accurately model human psychological processes in animals. Further, especially in the case of developing treatments for neuropsychological disorders like PD, medications tested in animals may reduce outward symptoms such as tremors, while nothing is known about the drug’s effects on the subjective experience of the animal (Nestler & Hyman, 2010). It would not be until the drug was tested on an actual human that the mental effects of the drug would be known. This poses understandable ethical concerns.

On the other side of the coin, ethical considerations for the animals involved with such research also pose challenges. Some argue that since we are not 100% sure diseases such as depression or schizophrenia affect humans and animals similarly, it’s unethical to subject the animals to these diseases in the first place. These same issues arise in cancer research, where zebrafish appear to model some, but not all, forms of cancer (Yen et al., 2014). Without understanding why, is it acceptable to subject the animals to experimentation? As one medical professional put it:

While Darwin’s continuity of species gave researchers firm ground to walk on when studying human processes in animals, we must always consider the preceding quote as we use animals to pursue our own medical and psychological advancements.