We examined immature wild chimpanzees' attention-sensitive gesturing, that is their ability to adjust the sensory modality of their gestures to the visual attention/inattention of their mother.
Chimpanzees were first capable of deploying audible-or-contact instead of silent-visual gestures when visual attention was unavailable, that is, cross-modal adjustment, before being able to inhibit their silent-visual gestures, that is, unimodal adjustment.
Infants did not display attention-sensitive gesturing while adolescents did, and juveniles presented an intermediate pattern with cross-modal adjustment preceding and predicting unimodal adjustment and with high variability in the age at the onset.
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