Investigating the Cognitive Mechanisms underlying Early Hominin Stone Tool Use through an Experimental Neuroarchaeological Approach

Abstract

Die Dissertation ist gesperrt bis zum 27. August 2027 !

This doctoral research investigates the cognitive mechanisms underlying early hominin stone tool use, introducing a novel methodological framework for real-time analysis of tool related behaviors within experimental neuroarchaeology. The study employs a multidisciplinary approach that integrates: (i) real-time neurophysiological recording techniques, specifically electroencephalography (EEG) and surface electromyography (sEMG); (ii) experimental archaeology tasks that model behaviors attributed to early hominins; and (iii) advanced analytical methods, including frequency-domain EEG measures and multivariate statistical analyses. The first study (Paper I) explores the neural correlates of two fundamental tool-use behaviors: percussive nut-cracking and precision cutting. EEG findings reveal heightened frontoparietal engagement during both tasks, with increased beta-band power in frontal and centroparietal regions during precision cutting compared to hammerstone use, as well as elevated contralateral frontal beta activity during the aiming phase. These results indicate key neural adaptations associated with the emergence of precise lithic tool manipulation in early hominins. The second study (Paper II) develops a replicable, integrative framework for examining brain–hand–tool interactions through a multivariate analysis pipeline that simultaneously processes EEG and sEMG data. Applied to empirical data, it captures complex neural muscular dynamics and confirms that the EEG signatures identified in the first study covary with power vs. precision grasping patterns. Therefore, while Paper I characterizes phase specific neural dynamics during stone tool use, establishing a baseline description of the EEG signatures that accompany percussive and cutting behaviors, Paper II turns those phase specific EEG effects into testable brain–hand links. In this way, it both validates and sharpens the inferences from Paper I — moving from indirect, design-based attribution to direct quantification of the interplay between neural signals and grasp mechanics. The openly documented workflow offers a reusable basis for future neuroarchaeological research and for broader studies of manual skill and symbolic behavior. The third study (Paper III) complements the execution-focused arc of Papers I–II by moving upstream to the conceptual stage. It investigates the neural basis of tool selectivity by analyzing cognitive processes involved in the internal decision-making for tool choice. EEG analyses show increased beta power localized over posterior, right-lateralized occipital regions during tool selection compared to control conditions, with no significant difference between tool types. This suggests a shared selection-level mechanism decoupled from the execution-specific differences documented in Papers I–II. Taken together, the thesis offers a holistic account of early stone tool use: Papers I–II address the practical, execution-level demands and establish direct brain–hand mappings, while Paper III addresses the conceptual, choice-level demands. Overall, this research project contributes novel insights into the neurocognitive evolution of early hominin tool use and introduces an integrative methodological approach, providing a basis for future research into the emergence of human manual dexterity and increasingly complex cognitive repertoires.