Perceptual and symbolic adaptations in prehistoric semiotic behavior: an experimental approach.
Recently, there has been a great interest in connecting archeological findings to knowledge and hypotheses about cognitive evolution including the evolution of language. Among the evidence discussed are line carvings, as they can be found in stone and ostrich shells dating back as long as 100 ka. It has been suggested that developments in line patterns over time are related to adaptations for potential symbolic value and function (Christopher S Henshilwood, d'Errico, & Watts, 2009; Christopher S. Henshilwood et al., 2011; Hodgson, 2014; Texier et al., 2013). In a series of experimental studies, we investigate whether the development of early line patterns stretching over a period of approx. 70.000 years is an expression of an adaptive process of functional optimization for human perception and cognition, that is, if line carvings evolve over time to become more salient, reproducible, intentionally expressive and memorizable. We will present evidence from three experiments using engraved line patterns from early archeological records as stimuli to test a set of related hypotheses: 1) Later patterns are more perceptually salient than earlier ones, 2) later patterns are easier to remember and reproduce than earlier ones, and lastly 3) later patterns are more likely to be experienced as intentionally produced by a human with an aesthetic/symbolic purpose. Results suggest that the archeological findings indeed show traces of adaptive development with later patterns being more perceptually salient, easier to remember and more likely to be interpreted as intentionally produced than earlier patterns.