In chimpanzee hand gestures shaking hands

#In chimpanzee hand gestures shaking hands plus#

This species difference suggests that multimodal expression of communicative intent was also strengthened after hominids diverged from apes.

#In chimpanzee hand gestures shaking hands plus#

Multimodal expressions of communicative intent (e.g., vocalization plus persistence) were normative for the child, but less common for the apes. This species difference suggests the co-evolution of speech and gesture after the evolutionary divergence of the hominid line. However, vocalization was rare for the apes, but accompanied the majority of the childвЂ™s communicative gestures. In all three species, the overwhelming majority of gestures were communicative (i.e., paired with eye contact, vocalization, and/or persistence). This ontogenetic sequence from gesture to symbol, present across the clade but more pronounced in child than ape, provides support for the role of gesture in language evolution. In contrast, by 15вЂ“18 months of age, the child used symbols more frequently than gestures. But even though their symbol production increased, the apes continued to communicate more frequently by gesture than by symbol. Nonetheless, across species, the ratio of symbol to gesture increased significantly with age. A developmental pattern in which gestural representation of a referent preceded symbolic representation of the same referent appeared in all three species (but was statistically significant only for the child). The childвЂ™s symbols were spoken words the apesвЂ™ symbols were lexigrams вЂ“ non-iconic visual signifiers.

A basic finding was the functional and formal similarity of many gestures between chimpanzee, bonobo, and human child. These three species constitute a complete clade: species possessing a common immediate ancestor.

Using a naturalistic video database, we examined whether gestures scaffold the symbolic development of a language-enculturated chimpanzee, a language-enculturated bonobo, and a human child during the second year of life.

3Department of Psychology, University of Southern Mississippi, Long Beach, MS, USA.

1Department of Psychology, University of California, Los Angeles, CA, USA.