In Looking at the Cultured Ape, Researchers Learn Much About Humanity

[Photo: Gerald and Buff Corsi © California Academy of Sciences]

ST. LOUIS — What if making dinner meant climbing to the top of a palm tree, brandishing one of the tree’s fronds and pounding the tree to make a tasty mush, all while standing on two feet? If it isn’t appetizing, it is an impressive use of tools and smarts that a population of chimpanzees in Guinea adopted to fill their bellies.

A panel of primate researchers discussed such human-like cultural behaviors of orangutans, gorillas and our closest relatives — chimpanzees — at a AAAS press briefing on Sunday 19 February. With expectations that ape species (particularly the orangutan) and their cultural diversity could taper to levels of near-extinction within the next 10 to 20 years, researchers hope that an increased understanding and awareness of the species and their human-like behaviors will bring our evolutionary elders the respect and attention they need for survival.

Andrew Whiten, professor of evolutionary and developmental psychology and Wardlaw Professor of Psychology at the University of St. Andrews, leads chimpanzee cultural research — and is finding striking similarities between their learned cultural behaviors and our own.

“Our culture didn’t come out of nowhere,” Whiten says of our relatives with whom we share 96 percent of our DNA sequence, according to a September 2005 report from an international research consortium. His research is contributing to a windfall of information that has been discovered about the animals, who, until 50 years ago, were virtually unstudied.

Culture, Whiten explains, refers to traditions passed within and between generations. Whiten has documented a large number of cultural traditions — chimps and orangutans demonstrate more than 40 distinct traditions; he’s also reported a wide ranage of behaviors, including tool use, grooming, foraging methods and communication. And he’s found that a chimp community’s cultural profile can include a cluster of unique traditions.

One chimp population, for example, might crack nuts and “fish” for termites, which involves inserting a stick into a termite mound and then removing it to expose the termite snack, while another population might solely fish for termites, but perform the task more efficiently. Because of their high levels of development, ape cultures appear to be more complex — and humanlike — than those of other animals.

Observational evidence led Whiten to suspect that chimps, like humans, can pass cultural traditions across generations; to date, as many as four studied generations have shown patterns of cultural transmission. Variations between nearby, closely-related populations, a population’s singular reliance on a universally available tool like a stick or leaf, and juveniles’ intense observation and imitation of adult behavior offered intriguing evidence for his case.

“You’re not born smart,” Carel van Schaik, an orangutan expert from the University of Zurich, explains. “You’re becoming smart because you’re learning.”

To confirm the observational evidence, Whiten and his colleagues looked to test cultural transmission among apes in captivity. Dominant chimpanzees from each of two groups were taught a different technique for extracting food from behind a blockage, and then returned to their respective groups to model the behavior for their peers. As Whiten expected, the learned techniques spread within the two groups, generating two distinct, long-term traditions. The experimental evidence enforces his observations of the culture-acquiring capacities of wild chimpanzees.

Read All About It! For more AAAS news from the 2006 Annual Meeting in St. Louis, Mo., click here.

Additionally, Whiten found evidence of another very human inclination: chimps conform to local cultural norms. Their behavior isn’t mindless imitation for imitation’s sake — a second experiment showed that chimps can imitate useful behaviors and ignore irrelevant ones. Interestingly, human children were less flexible and more irrational, copying both useful and irrelevant behaviors.

Other researchers have used Whiten’s methods to study other kinds of apes: van Schaik replicated the kinds of experiments with orangutan populations, and Tara Stoinski, from Zoo Atlanta/Dian Fossey Gorilla Fund International, has compared gorilla populations within and among different zoos to document ape behaviors.

All three scientists have found evidence of social behavioral transmission, suggesting that apes have the capacity to acquire culture. “We can argue that cultural species will become smarter species,” van Schaik says. Which could mean salvation for quickly dwindling ape populations, if human populations can sympathize with their intelligent relatives.

“We’re finding out that there are all these cultural variations, but we’re losing the diversity, just like with some human populations,” Whiten explains. High extinction risks underscore the need for ape conservation.

The researchers’ plan for protection: increased awareness. “The only thing we can do,” Stoinski says, “is engender respect and wonder about these animals who are so similar to us.”

Alison Drain

20 February 2006