Anyone who has spent time with nonhuman animals knows they display different personalities. In my research with dogs and wild coyotes, individual differences in personalities, ranging from shy and timid to playful, bold, and downright obnoxious, have consistently been observed over many years. When young coyotes emerge from their den at around three weeks of age, there are distinct differences in personality among littermates even at this young age. When I worked on a project on Adélie penguins living on Ross Island, Antarctica, other researchers and I saw similar traits in these birds. Some were bold and brazenly stole rocks from the nests of other penguins, some were extroverted and outgoing and had little to no tolerance for penguin intruders and South Polar skuas who were trying to snatch up babies and eggs, whereas others seemed very cautious, reserved, and introverted.
Over the years, more and more comparative research has been conducted on personality traits in a wide array of animals, and the data clearly show that individuals of many different species display the same spectrum of traits and in many cases an individual shows the same personality over time.
Years ago, I remember learning about the seminal field research of Jane Goodall at the Gombe National Park. Dr. Goodall named, rather than numbered, the chimpanzees she observed, and freely talked and wrote about their unique personalities. It's common knowledge that she was severely criticized by other researchers, mainly males, many of whom had never been in the field. In an essay by Karen Weintraub published yesterday in The New York Times called "Wild and Captive Chimpanzees Share Personality Traits With Humans," Ms. Weintraub writes, "Many scientists at the time were horrified, she [Jane Goodall] recalled. Considered an amateur—she didn’t yet have her Ph.D.—they contended she was inventing personality traits for animals." Dr. Goodall notes, “I was guilty of the worst kind of anthropomorphism.”
As a graduate student at the time she was doing her research, I used her as an example and named the animals I was studying and was encouraged to talk about bold, shy, and playful dogs, coyotes, and wolves. It's seemed like a no-brainer at the time, and now we've come to learn that nonhumans do indeed show different personality traits and, in many cases, they are consistent over time. Numerous research and popular essays can be seen here and here.
"Personality in the chimpanzees of Gombe National Park"
The research essay, available online, about which Ms. Weintraub is writing is titled "Personality in the chimpanzees of Gombe National Park," by researcher Alexander Weiss and his colleagues. Their goal "is to lay the groundwork for the systematic study of personality in wild chimpanzees." This sort of detailed research is really what's needed across many different species, and this is a most welcomed study. Personality traits studied included dominance, extraversion, conscientiousness, agreeableness, neuroticism, and openness.
While detailed research has shown that distinct personalities exist in many different animals, the power of this study is that it expands the database especially for wild nonhuman chimpanzees who have been observed over long periods of time. Overall, 128 wild chimpanzees were studied, all of whom lived or live in the Kasekela and Mitumba communities of Tanzania's Gombe National Park, where Dr. Goodall began her studies in 1960. More than 11,000 data points were analyzed. Data came from skilled field workers who followed individual chimpanzees for many years and really got to know them.
The researchers also were able to update data on chimpanzees who were studied in 1973 with data on others who were studied subsequently. They discovered that many personality traits are stable over decades.
Ms. Weintraub nicely captures the essence of the research with quotations from those who were involved in the study and others who weren't. Georgia State professor Robert Latzman who wasn't involved in the study notes, “What’s exciting about these data is there’s some suggestion that wild apes look very similar to what we would expect in terms of basic dispositional traits and continuity of those traits—and I don’t mean just to captive chimpanzees, but to humans...The work in the wild underscores how similar these animals truly are to humans.”
Because the research essay is available online, interested readers can see all of the details. The researchers have also made their dataset and personality questionnaire available to the public. Dr. Weiss and his colleagues conclude their landmark study as follows: "These correlations established the repeatability and construct validity of the present ratings, indicating that the present data can facilitate historical and prospective studies that will lead to better understanding of the evolution of personality in chimpanzees and other primates." I'm sure that other researchers will pick up on what they did because of its power in learning more about the evolution of personality in different species including nonprimates.
What goes around comes around
Jane Goodall's research was groundbreaking and the research paper by Dr. Weiss also is incredibly important. The data clearly show that what goes around comes around. Dr. Goodall is thrilled and notes, “Today you can get your Ph.D. studying animal personality. I think we’ve come around full-cycle ... It absolutely vindicates all that I’ve ever believed.” We should all be glad that she was persistent and didn't yield to numbering the chimpanzees she studied and agreeing with those who said it was taboo to talk about animal personalities.
I look forward to future comparative studies on animal personalities. The study by Dr. Weiss and his colleagues sets the standard for years to come.