Lower and Middle Palaeolithic stone toolmaking and language: a preliminary experimental archaeological and psycholinguistic study

Many authors suggest that there is a co-evolutionary relationship between Palaeolithic stone toolmaking and language. This assumption is, firstly, supported by experimental studies showing positive effects of verbal compared to non-verbal demonstration during stone toolmaking acquisition in present-day humans. Secondly, it is backed by neurophysiological studies which demonstrate that both toolmaking and language activate overlapping brain regions and that they exhibit similar hemodynamic lateralization patterns in present-day humans. These studies have mainly been focused on Oldowan flaking and Acheulean handaxe manufacture. Studies on the effects of the verbal and non-verbal transmission modes currently suggest that both Oldowan and Acheulean acquisition are facilitated by non-linguistic gestures rather than purely spoken language. Furthermore, neuroimaging studies have found that the prefrontal cortex, an area typically associated with executive functioning, and the temporal cortex are activated more during Acheulean compared to Oldowan tasks. We recruited twelve Croatian-speaking subjects with no prior experience in knapping. Subjects were taught the Oldowan chopper and Mousterian sidescraper manufacture in a verbal teaching and non-verbal basic teaching condition. Tool quality was assessed by measurements of various physical attributes and a subjective evaluation by two assessors on a 5-point scale. Subjects were also tested on a neuropsychological battery assessing visual attention, verbal working memory, visuospatial processing, planning, cognitive flexibility, general executive functioning and lexical-semantic processing. We hypothesize that there will be no significant differences between the verbal and non-verbal groups in the chopper manufacture task, and that the verbal group will perform significantly better compared to the non-verbal group in the sidescraper manufacture task. Additionally, we hypothesize that chopper manufacture will be significantly positively correlated only with the visual processing tasks, while sidescraper manufacture will also be significantly positively correlated with the prefrontal functioning tasks. The obtained results will be interpreted within the framework of current evolutionary and cognitive theories.