BY SANJIDA O’CONNELL
Daily Telegraph
Are human beings impossible to ape?
Chimpanzees share 98 per cent of our DNA. But just how close does that make them to being human? And should primate rights ape human rights?
About 50 years ago, something happened that radically changed our ideas about what it meant to be human. A young secretary who had ventured into the African jungle witnessed a chimpanzee fashioning a tool out of a blade of grass, and using it to fish for termites. Jane Goodall had been sent to Tanzania by Dr. Louis Leakey, who, on hearing her startling news, came up with an equally startling statement: “Now we must redefine ‘tool’, redefine ‘man’, or accept chimpanzees as humans.”
DESIREY MINKOH/AFP/GETTY IMAGESTwo baby Bonobo chimpanzees at the Bonobo sanctuary in Kinshasa, in the Democratic Republic of Congo.
During the ’60s, the then Dr. Goodall, later founder of the Jane Goodall Institute, discovered more similarities between ourselves and chimpanzees: they can use stone tools; they have a rudimentary culture; their mothers teach their infants; they feel similar emotions to us, such as fear, sadness, happiness; and they grieve over lost loved ones.
Subsequently, genetic research started to shore up her theory that “the line between humans and other non-human beings, once thought so sharp, has become blurred.” Movements sprang up such as the Great Ape Project, founded in 1993 by the bioethicist Peter Singer, which argued that apes should be awarded certain basic rights. And as genome mapping was developed, the genetic difference observed between humans and chimpanzees, our closest living ancestors, continued to shrink: it turned out that only 1.6 per cent of our genes were different.
This activity led to two basic conclusions: that humans and apes were not that different after all, and that if 98.4 per cent of our genes were shared with chimps, the remaining 1.6 per cent should explain why our development has differed so dramatically from that of our cousins.
Yet a new book, published last week, is attacking both assumptions. “Because we are virtually genetically identical, primatologists argue that in a logical sense, chimpanzees are very close to us cognitively,” says Jeremy Taylor, author of Not a Chimp: The Hunt to Find the Genes that Make Us Human. “The way this idea has bled into popular culture enrages me.”
Taylor is particularly scathing on the subject of primate rights. “I don’t understand why conservation of the great apes has become synonymous with human rights and their similarity to us, whereas conservation of wetlands or a million other species doesn’t carry any such conflations,” he says.
Goodall’s work was followed by a spate of studies demonstrating how close chimps’ mental capacities seem to be to ours. They can, it is thought, show self-awareness, as demonstrated by what has become a classic test. Researchers put a blob of paint on a chimp’s face without the animal noticing or being able to see the spot, and then give it a mirror. Macaques and other monkeys will react aggressively to their mirror image, as if they are seeing another creature, whereas chimpanzees will calmly sit down and rub the paint off.
Thirty-one years ago, two scientists, David Premack and Guy Woodruff, published a seminal paper asking whether chimpanzees had what they termed “Theory of Mind”: the ability to understand that another being has thoughts and beliefs, desires and feelings. Because we have this ability, we think about what other people are thinking: we don’t treat our fellows as if they were objects or automatons following a set of rules.
The majority of scientists working in this field would argue that chimps do not have the same capacity as humans for thinking about how others think, but that, nevertheless, chimps still have some understanding of mental states. “It is time for humans to quit thinking that their nearest primate relatives only react to behaviour,” says Dr. Josep Call, from the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, who has been studying chimpanzees for many years. “All the evidence suggests that chimpanzees understand both the goals and intentions of others as well as the perception and knowledge of others.”
Yet there are skeptics, chief among them professor Daniel Povinelli of the University of Louisiana. In one of his experiments, chimps were made to beg for food from two researchers. One wore a bucket on his head, which prevented him from seeing the chimps, and the other did not. The chimps begged indiscriminately from both researchers, indicating that they could not understand what the researchers could see.
It was such problems that led Taylor to turn to genetics to understand the mental and genetic differences between ourselves and chimpanzees. For his new book, the television producer trawled through the latest research papers, and discovered that these differences could be far greater than previously thought.
Over the past five years, he points out, our understanding of genetics has become more sophisticated. While there might only be a 1.6 per cent difference in the genome itself, the way it shapes our minds and bodies is radically different. “ The key thing for me,” says Taylor, “is that when you compare chimps and great apes with humans you notice how much more gene expression there is in humans.”
Gene expression is when certain genes damp down or speed up chemical processes. A team from the Max Planck Institute for Evolutionary Anthropology showed that in human brains, there is a five-fold increase in the rate of gene expression.