How similar are the gestures of apes and human infants? More than you might suspect - 2 views
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Lara Cowell on 21 Jan 14Psychologists who analyzed video footage of a female chimpanzee, a female bonobo and a female human infant in a study to compare different types of gestures at comparable stages of communicative development found remarkable similarities among the three species. Gestures made by all three species included reaching, pointing with fingers or the head, and raising the arms to ask to be picked up. The researchers called "striking" the finding that the gestures of all three species were "predominantly communicative," Greenfield said. To be classified as communicative, a gesture had to include eye contact with the conversational partner, be accompanied by vocalization (non-speech sounds) or include a visible behavioral effort to elicit a response. The same standard was used for all three species. For all three, gestures were usually accompanied by one or more behavioral signs of an intention to communicate. At the beginning stage of communication development, gesture was the primary mode of communication for human infant, baby chimpanzee and baby bonobo. The child progressed much more rapidly in the development of symbols. Words began to dominate her communication in the second half of the study, while the two apes continued to rely predominantly on gesture. "This was the first indication of a distinctive human pathway to language," Greenfield said. All three species increased their use of symbols, as opposed to gestures, as they grew older, but this change was far more pronounced for the human child. The child's transition from gesture to symbol could be a developmental model of the evolutionary pathway to human language and thus evidence for the "gestural origins of human language," Greenfield said. While gesture may be the first step in language evolution, the psychologists also found evidence that the evolutionary pathway from gesture to human language included the "co-evolution of gestural and vocal communication." Most of the child's gestures were accompanied b