Exploring the Emotional Lives of Animals: What Science Reveals

“To our knowledge, this is the first evaluation of how researchers across various fields view emotions and consciousness in animals that aren’t human,” states Marcela Benítez, an assistant professor of anthropology at Emory University and the lead author of the study. “This serves as a snapshot in time, allowing us to look back in 20 years to see how expert opinions have evolved.”

The majority of those surveyed believed that “most” or “nearly all” non-human primates (98%), other mammals (89%), birds (78%), cephalopods (72%), and fish (53%) possess emotions. Additionally, a significant number reported that some members of nearly every animal group, including insects (67%) and other invertebrates (71%), are capable of feeling emotions.

The survey also examined potential risks in animal behavior research, such as anthropomorphism (the tendency to attribute human traits to animals) and anthropodenial (the refusal to recognize human-like traits in animals).

“It’s interesting that 89% of respondents deemed anthropodenial a significant issue in animal behavior research, while only 49% believed that anthropomorphism posed a threat,” Benítez observes. “This indicates a considerable shift in thinking.”

She points out that anthropomorphism has been one of the main arguments against attributing emotions to animals.

The study’s first author, Matthew Zipple, is a neurobiologist at Cornell University’s Laboratory for Animal Social Evolution and Recognition. Co-authors include Mackenzie Webster, an Emory postdoctoral researcher focused on cognition in non-human primates, and Caleb Hazelwood, a philosopher at Duke University.

Philosophers have long debated whether animals feel emotions. Aristotle suggested that animals and humans share similar emotional experiences, whereas Descartes viewed animals as machine-like entities lacking emotions and consciousness.

In the mid-1800s, naturalist Charles Darwin claimed that “lower animals, much like humans, evidently feel pleasure and pain, joy and sorrow.” Yet by the mid-20^th century, prominent behavioral theorists dismissed the concept of studying animal emotions, arguing that even if they existed, they couldn’t be measured or verified scientifically.

Frans de Waal, a prominent primatologist and an emory emeritus psychology professor, played a pivotal role in changing this narrative through his innovative research in animal cognition. His influential works, from “Chimpanzee Politics” published in 1982 to “Mama’s Last Hug: Animal Emotions and What They Reveal About Our Own” in 2019, significantly shifted attitudes regarding the scientific exploration of animal thoughts.

“Frans de Waal undoubtedly opened the door for future inquiry,” Benítez remarks. “He empowered a new generation of scientists to consider the inner lives of animals.”

Benítez’s research intersects anthropology, psychology, and evolutionary biology, focusing on cooperation and social behavior in capuchin monkeys. “Emotional bonds are crucial for cooperation,” she explains. “So I need to incorporate emotions into my studies.”

Previously, she was a postdoctoral fellow in Sarah Brosnan’s lab, an Emory PhD graduate, and de Waal’s student during his time at the Living Links Center. Brosnan now serves as a psychology professor at Georgia State University, where her work centers on the evolution of cooperation and decision-making in primates.

Benítez describes de Waal’s legacy as a key factor behind her desire to join the Emory faculty, where she feels she is following in his footsteps.

De Waal’s widely popular books have significantly influenced public views on animal minds.

Many of the graduate students in Benítez’s Social Cognition and Primate Behavior Lab were inspired to study animal cognition after reading de Waal’s works in their youth. “His impact is truly extensive,” she says.

As the field evolves, Benítez and her colleagues aimed to gauge animal behavior researchers’ assessments regarding the emotional capabilities of different animal taxonomic groups. They crafted a survey featuring multiple-choice questions, open-ended text inquiries, and rating scales and distributed it to leading graduate programs in animal behavior research. They also posted calls for participation on X, targeting researchers involved in these disciplines.

The 100 individuals who participated in the survey represented a variety of specialties, including behavioral ecology, evolutionary biology, neuroscience, biological anthropology, cognitive psychology, and biological psychology. Participants included graduate students (45), faculty (28), postdoctoral fellows (20), retirees (2), other PhD researchers (3), and undergraduates (2).

The most commonly studied taxa among respondents were birds (43%), non-human primates (32%), and other mammals, although representatives of each taxonomic group included in the survey were studied by some of the respondents.

The survey defined animal consciousness in a straightforward manner, focusing on self-awareness. A large portion of respondents associated consciousness with a wide range of animals, although slightly fewer than those who attributed emotions.

At the conclusion of the survey, respondents were asked for their definitions of emotion.

Just over half of the definitions mentioned emotions as responses to internal or external stimuli. Many of the responses also described emotions as subjective experiences linked to consciousness or the mind. About 40% indicated that emotions serve to motivate behavioral actions.

Only 81 out of the 100 respondents provided definitions, possibly due to the difficulty in articulating a clear description.

“I don’t have a precise definition either,” Benítez shares. “I view emotions as internal processes influenced by external stimuli that shape our perceptions of situations. I lean towards a fundamental definition to facilitate exploring this capacity in non-human primates.”

Even within human studies, Benítez acknowledges that pinpointing biological markers and adequately describing and measuring the multifaceted nature of emotions is a challenge. Emotional responses can range from instinctual feelings of fear or disgust to profound emotions such as love and empathy towards others.

Researching animal emotions poses additional obstacles, particularly since researchers can’t directly communicate with animals to inquire about their feelings.

While controlled laboratory experiments can yield precise results, they might not accurately reflect animals’ natural behaviors. Conversely, field studies offer valid ecological and social contexts but are often difficult to control.

“I am attempting to bridge that gap,” Benítez explains. Her research is distinct as she evaluates behavior in both captive tufted capuchins and wild white-faced capuchins as a co-director of the Capuchins de Taboga Costa Rica project in Liberia.

With her collaborators at La Universidad Technica Nacional, Benítez is starting to incorporate AI technologies, facial recognition software, and touch screen computers for data collection in the field. These innovative tools may allow her to address questions related to capuchin monkey behaviors, such as how they choose to cooperate or compete within their natural environment.

“We have only begun to explore the depths of what animals may experience,” Benítez remarks. “This is an exciting time as new methodologies could enhance our understanding of animal feelings and the decisions they take.”

“As an anthropologist,” she concludes, “a significant part of my motivation to understand the inner lives of animals is to gain insights into our own evolutionary journey. In what ways are we a unique species? Investigating the evolution of emotions is essential to answering that question.”