Allometry and multidimensional form in Acheulean bifaces from Kilombe, Kenya

Abstract

Abstract We demonstrate that allometry is a major factor in the variation of hand-axes from the late Lower Pleistocene Acheulean site of Kilombe in Kenya. Acheulean hand-axes were made in a range of sizes, from ca. 8-30 cm in length, and are superficially similar in form at different sizes, even though functional requirements might be expected to vary. To make an appropriate study of three-dimensional form we require a method for analysing size-related change in multiple measures of form. Jolicoeur's multivariate generalization of the allometric equation, (y = bx4), provides a suitable technique, based on the angular relationships of co-ordinates for each measure to the first principal component of the covariance matrix. We have applied this approach to an analysis of several biface assemblages from separate parts of the Kilombe site complex. Allometry is an important component in all the localities, but one area observes a different set of adjustments. We argue that the allometry is probably imposed in response to functional requirements: it suggests that Homo erectus was constrained to follow a number of different guiding principles in the manufacturing process.