In Chicago, a meeting of the human and chimp minds
If chimpanzees truly followed what humans call the law of the jungle, a mentally disabled chimp named Knuckles would never stand a chance.
Yet Knuckles has found acceptance and perhaps even sympathy from his fellow chimps in Florida, making him an unlikely star of Lincoln Park Zoo’s international Mind of the Chimpanzee conference.
The meeting, which runs today through Sunday with 300 researchers from around the world, is billed as the first major conference devoted to chimp cognition, and the first academic chimp conference at the zoo since 1991.
Although much of the meeting will examine the intelligence of humanity’s closest living relatives, Knuckles offers insight as the only known captive chimp with cerebral palsy, which immobilized one arm and left him mentally unable to follow protocols of chimp society.
Normally, older chimps would put on intimidating displays with a juvenile male, screaming, grabbing and biting the youngster to put him in his place, said Devyn Carter, who has studied Knuckles and is presenting his research at the Lincoln Park Zoo conference. But even the alpha male tolerates and gently grooms Knuckles.
“To my knowledge he’s never received a scratch,” said Carter, a research assistant at Emory University’s Yerkes National Primate Research Center. “They seem to sense somehow that he’s different.”
Such behavior touches on a central theme of many presentations at the Lincoln Park Zoo conference: How well do chimps understand what other chimps know, feel and perceive?
Some experts believe chimps and other higher primates have empathy, the ability to imagine themselves in another animal’s place. And that may be the first step in the evolution of morality.
Chimps may use their empathic skills for good, but also to manipulate others. Researchers have found that chimps have a talent for deception, which requires mental sophistication, said conference co-organizer Elizabeth Lonsdorf, director of the zoo’s Lester E. Fisher Center for the Study and Conservation of Apes.
The way scientists deal with such questions has changed dramatically since the Lincoln Park Zoo held its previous chimp conferences, in 1991 and 1986. Twenty years ago, researchers still considered it taboo to use the terminology of human thoughts and emotions to describe animal behavior. Field scientist Jane Goodall, who will deliver a public lecture on the meeting’s last day, once was ridiculed by other scientists for naming the chimps she studied.
But a consensus is slowly building that traits such as empathy not only apply to humanity’s ape relatives, but may have guided the evolution of our extended family of primates.
“I think empathy has great adaptive advantages,” said conference participant Frans de Waal, a professor of psychology at Emory and director of the Living Links Center at Yerkes.
De Waal has written extensively about how the moral behavior of nonhuman primates sheds light on humanity’s evolutionary roots. He believes the complex social lives of chimps offer evidence that human intelligence evolved not to help our ancestors get food, but primarily as a way of handling social challenges and figuring out other humans.
“Lots of animals pick fruits and don’t have brains like ours,” De Waal said. “But once you live in groups, you have to deal with group life, and that takes tolerance and compassion, and also competition.”
A key unsolved question is whether chimps possess what psychologists call a “theory of mind” -- the knowledge that individuals see the world in different ways. Human children don’t develop that awareness until age 4 or so; for example, a toddler who sees a toy being hidden has trouble grasping that other people don’t know where it is.
Testing that ability in chimps is difficult because of the language gap, but some scientists at the conference believe chimps have a true theory of mind, said Tetsuro Matsuzawa, a primate researcher at Kyoto University.
Matsuzawa said chimps’ ability to deceive suggests an awareness of how other minds work.
He showed a video of a chimp mother in the forests of Guinea tricking her 9-year-old son into grooming her so she could nab the rocks he was using to crack open some palm nuts.
The video shows the mother flashing the chimp version of a smile as she grabs the rocks for herself.
But Matsuzawa’s most remarkable footage is of a 5-year-old captive male chimp named Ayumu, who seems capable of memory feats far beyond what most people could do.
In one task, Ayumu sees a sequence of numbers from 1 to 9 scattered randomly on a computer screen. The numbers appear for less than a second, barely enough time to see them all, before being replaced by nine white squares. Ayumu’s job is to remember where the hidden numbers were, and to touch their squares in sequence from 1 to 9.
He succeeds immediately, almost every time, touching the squares casually but quickly. Matsuzawa’s video shows human subjects barely passing the test with just four or five numbers. “No graduate student of Kyoto University can do it,” Matsuzawa said.
Once again, Matsuzawa said, the demands of social life may help explain the chimp’s precocious abilities. In the wild, chimps need to remember where each member of the group is at all times, in part to defend against possible challenges by someone else in the hierarchy.
