Do great apes use iconic gestures?

Many researchers in cognitive science and linguistics now recognize that iconicity – perceived resemblance between the form and meaning of a signal (e.g., a word, sign, or gesture) – is an essential property of language, playing vital roles in its processing, learning, and historical development. Iconicity is also fundamental to the human ability to create meaningful new signals without reliance on convention. This “iconic turn” raises a critical question for the study of language origins: Do great apes use iconic gestures? Apes are well documented to use a flexible and wide-ranging repertoire of gestures, and many appear to be iconic representations of actions, including directive touches, visual directives, and pantomimed actions. However, the most widely accepted theories – ontogenetic ritualization and biological inheritance through phylogenetic ritualization – argue that this apparent form-meaning resemblance is not psychologically real to the apes using the gestures. They argue instead that effective actions are channeled into gestures through repeated use, either through an individual’s experience or over generations of evolution. Yet, it is increasingly recognized that these theories cannot account for the variability and contextual tuning of ape gestures. Alternatively, reasoning from cognitive theories of human gesture and iconicity as rooted in sensorimotor simulation and mental imagery, apes may use a range of gestures that appear homologous to the iconic gestures of humans, even if comparatively restricted in imaginative scope and anchored heavily in a here-and-now context. This fundamental capacity for iconic gesturing may have been a critical precursor to the evolution of language.