[Symbol-based communication in non-human primates: a C. S. Peirce's semiotic analysis]

Are (or were) there any other symbolic species? This question has been addressed by researchers from many different fields and is responsible for a historical controversy on the existence of a threshold between "symbolic creatures" vs "simple forms of language creatures". According to the mainstream ethology and comparative psychology only the Homo sapiens is cognitively equiped to produce and interpret symbols. Here, I introduce an empirically testable model of symbolic semiosis ("symbolic action of sign") supported by C.S.Peirce logical-phenomenological theory of categories. I suggest that a specific sign-user pattern of behavior, observed in non-human primate communication, indicate a transition from indexical to symbolic semiosis.