How did our evolutionary ancestors make sense of their world? What strategies did they use, for example, to find food? Fossils do not preserve thoughts, so we have so far been unable to glean any insights into the cognitive structure of our ancestors. However, in a study recently published in Current Biology (September 5, 2006), researchers at the Max Planck Institute for Psycholinguistics and their colleagues at the Max Planck Institute for Evolutionary Anthropology were able to find answers to these questions using an alternative research method: comparative psychological research. In this way, they discovered that some of the strategies shaped by evolution are evidently masked very early on by the cognitive development process unique to humans.
Being able to remember and relocate particular places where there is food is an asset to any species. There are two basic strategies for remembering the location of something: either remembering the features of the item (it was a tree, a stone, etc.), or knowing the spatial placement (left, right, middle, etc.). All animal species tested so far - from goldfish, pigeons and rats though to humans - seem to employ both strategies. However, if the type of recall task is designed so that the two strategies are in opposition, then some species (e.g. fish, rats and dogs) have a preference for locational strategies, while others (e.g. toads, chickens and children) favor those which use distinctive features.
Until now, no studies had systematically investigated these preferences along the phylogenetic tree. Recently, however, Daniel Haun and his colleagues have carried out the first research of its kind into the cognitive preferences of a whole biological family, the hominids. They compared the five species of great apes - orangutans, gorillas, bonobos, chimpanzees and humans - to establish which cognitive strategies they prefer in order to uncover hidden characteristics. The researchers worked on the
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Contact: Daniel Haun
haun@eva.mpg.de
49-341-355-0462
Max-Planck-Gesellschaft
6-Sep-2006