Orangutans and chimps are smarter than monkeys and lemurs
Orangutans and chimps are smarter than monkeys and lemurs
mongabay.com
August 1, 2006
The great apes are the smartest of all nonhuman primates according to scientists at Duke University Medical Center.
The researchers found that orangutans and chimpanzees consistently outperformed monkeys and lemurs on a variety of intelligence tests, conclusively proving that apes are more intelligent than monkeys and prosimians.
“It’s clear that some species can and do develop enhanced abilities for solving particular problems,” said Dr. Robert O. Deaner, who led the study as part of his doctoral dissertation. “But our results imply that natural selection may favor a general type of intelligence in some circumstances. We suspect that this was crucial in human evolution.”
  In a battle of minds, the gorilla beats the lemur. Photos — silverback gorilla in Gabon and a Verreaux’s sifaka in Madagascar — by Rhett A. Butler |
Scientists have long observed that some species perform better than others in intelligence testing but they have had difficulty proving that these differences could be attributed to intelligence, according to Deaner.
“The trouble is that one species may outperform another in a problem-solving test not because it’s smarter, but because one species is poorly suited to that particular testing situation,” he said. For example, one species may be more comfortable grabbing a joystick.
According to a release from Duke University, “Deaner and his colleagues reasoned that they could refute this premise — that performance differences resulted from particular testing situations — by demonstrating that some primate species surpassed others across a wide range of problem-solving tests. Primates are an excellent comparison group because their similar perceptual and motor skills means that the same tests are generally appropriate for all of them, Deaner said. But developing a suitable data set to test this idea was not easy.”
The researchers examined hundreds of published studies and found evidence that some species truly outperform others on a wide range of intelligence tests.
“Our research strengthens the long-standing notion that some animal species truly are more intelligent than others,” Deaner said. “The smartest species were clearly the great apes — orangutans, chimpanzees, and gorillas — which performed much better than monkeys and prosimians.”
This article used quotes and information from a Duke University news release.