The functional brain networks that underlie Early Stone Age tool manufacture

Abstract

After 800,000 years of making simple Oldowan tools, early humans began manufacturing Acheulian handaxes around 1.75 million years ago. This advance is hypothesized to reflect an evolutionary change in hominin cognition and language abilities. We used a neuroarchaeology approach to investigate this hypothesis, recording brain activity using functional near-infrared spectroscopy as modern human participants learned to make Oldowan and Acheulian stone tools in either a verbal or nonverbal training context. Here we show that Acheulian tool production requires the integration of visual, auditory and sensorimotor information in the middle and superior temporal cortex, the guidance of visual working memory representations in the ventral precentral gyrus, and higher-order action planning via the supplementary motor area, activating a brain network that is also involved in modern piano playing. The right analogue to Broca’s area—which has linked tool manufacture and language in prior work1,2—was only engaged during verbal training. Acheulian toolmaking, therefore, may have more evolutionary ties to playing Mozart than quoting Shakespeare

Encoding of Novel Verbal Instructions for Prospective Action in the Lateral Prefrontal Cortex: Evidence from Univariate and Multivariate Functional Magnetic Resonance Imaging Analysis

“…information for higher-level behaviors (Putt et al, 2017;Stout & Chaminade, 2012). In line with previous hypotheses (Brass et al, 2009), we speculate that these incorporation processes may intervene at an intermediate stage between the processing of purely verbal information (likely involving language areas of the left hemisphere-a possibility entertained by Hartstra et al, 2011) and a sensorimotor stage in which verbally conveyed stimulusresponse mappings have been transformed into concrete sensorimotor representations for impending action.…”

“…Consistent with Ruge and Wolfensteller's (2010) findings, these authors reported a cluster of activity within the rMFG-dPMC in the implementation group only. Together with evidence for right LPFC involvement in praxis-related integration of verbal instructions (Putt, Wijeakumar, Franciscus, & Spencer, 2017), these findings further suggest a role of this brain sector in translating verbal instructions into motor programs for accurate behavior.…”

“…The particular locus of activity reported in this study lay within the ventral portion of the inferior frontal junction (IFJ)-an area that has long received attention for its role in cognitive control and working memory (Brass, Derrfuss, Forstmann, & von Cramon, 2005;Derrfuss, Brass, & von Cramon, 2004). This departure from the more systematic findings of the right LPFC involvement in verbal instruction implementation (Putt et al, 2017;Demanet et al, 2016;Ruge & Wolfensteller, 2010) warrants a more targeted investigation into these regions' neural dynamics during instruction implementation versus memorization at various stages of training.…”

Grammars of action in human behavior and evolution

“…This includes evidence of increased functional activation during action execution 17,32 and observation 18 , as well as structural remodeling of underlying white matter in response to tool-making training 19 . To date, these findings have been interpreted using reverse inference from known functions of rIFG, including especially its involvement in the cognitive control functions of inhibition 33 and action updating 34 that are critical to response selection during multi-component behavior 35 .…”

Effects of Handedness and Viewpoint on the Imitation of Origami-Making

“…There is a broad spectrum of social learning strategies across human cultures and across animal species, ranging from unsupervised observation to interactive teaching [36][37][38][39][40][41]. Prehistoric hominins could have used any of these learning strategies [28,[42][43][44]. Before the emergence of teaching, hominin children would have engaged in social learning through observation.…”