Abstract
<title>Abstract</title> <p>Stone knapping expertise has been used to model the evolution of hominin cognition, particularly technical skill, executive functions and language. Recent studies have relied on exploratory statistical analyses of distance-derived metrics within relational frameworks. Consequently, morphometric evidence of latent knapping skill as embodied in an individual handaxe has been limited to an ephemeral position within a sample-dependent covariance matrix, rather than a stable value representing an artefact-intrinsic property. To complement this relational approach, a novel dimensionally commensurate construct is introduced to quantify latent knapping skill as manifest in its two strongest predictors: bifacial refinement and radial mirror symmetry. A volume-derived coefficient is introduced as a sample-independent, persistent scalar generated via the full-resolution solid geometry of the artefact model within a unified 3D morphospace. Employing Lithikos and its referenced volumetric morphometry to 587 Levantine Middle and Late Acheulean handaxes revealed distinct distributional structures and various technological routes by parsing the interactions between refinement, elongation, and mirror symmetry. A subsequent analysis of an experimental sample which included notable exemplars of exceptional knapping skill verified the upper range and underlying structure of the volumetric construct. This persistent, sample-independent coefficient and its portable scalar value extend the inferential scope and analytical breadth of the knapping skill construct by adding distributional examinations at the artefact level to traditional relational approaches constrained to examinations of assemblage-level central tendencies.</p>