Friday, March 28, 2008

Humans 'learnt to gamble from chimps'

Humans may have inherited their propensity to gamble from chimpanzees, scientists say.

  • Chimps beat humans in memory test
  • Female chimpanzees 'sell' sex for fruit
  • Chimpanzees need role models
  • In a study, common chimpanzees were found to be more likely to take risks in seeking food than bonobos, their endangered close relative found in the Democratic Republic of the Congo.

    Chimpanzees (left) took risks in the study and bonobos (right) played it safe
    Chimpanzees (left) took risks in the study and bonobos (right) played it safe

    Researchers say the results demonstrate how species' food-gathering techniques and experiences shape how willing they are to engage in risky behaviour.

    They believe modern humans are willing to gamble to gain favourable outcomes because our ancestors shared potentially rewarding foraging and hunting techniques with chimps.

    In the experiment, five chimps and five bonobos at Leipzig Zoo in Germany were presented with repeated choices between two upside-down bowls, one of which consistently covered four grape halves and another covered between one and seven.

    The two species diverged from a common ancestor less than one million years ago and share many characteristics, including body size and appearance.

    However in the wild bonobos rely heavily on feeding from ground-based vegetation, which is a fairly consistent source of food, whereas chimps spend time foraging for fruit and hunting of monkeys - both of which take time and involve greater risk.

    The researchers, whose findings are published today in the Royal Society journal Biology Letters, found the captive chimps were more likely to opt for the riskier option in the tests, while the bonobos usually played it safe.

    Psychologist Sarah Heilbronner, of Duke University, North Carolina, said: "In doing so, bonobos may avoid some of the risk incurred by chimpanzees in their frugivorous foraging.

    "Our results suggest that species-specific feeding ecologies can strongly influence risk preferences.

    "Though humans systematically violate many of the normative principles of economic theory, few researchers have considered preferences in relation to the environment in which they evolved.

    "As humans did not evolve in the context of modern economies, many of our preferences are likely tailored to providing adaptive foraging and other evolutionarily relevant decisions.

    "An evolutionary approach to economic preferences can offer keen insights into the nature of decision making."

    Original here

    No comments: