Hominin Cognitive Development: Brains, Bodies and Behaviour - A Comprehensive Approach

Abstract

The cognitive developments of early hominins, which may have begun as early as the transition to bipedalism following our ancestors’ split with the great apes, ultimately enabled these early humans to consider concepts and undertake strategies that were previously unimaginable. Although this evolutionary trajectory has long been an inquiry of interest, cognitive research has often relied on hypotheses drawn from psychological theory or neural evidence provided by brain moulds (endocasts) made from early hominin crania, which can preserve sulci and gyri patterns of the hominin brain. These neuroanatomical landmarks are often difficult to discern with the naked eye; however, technological advancements in medical imaging can now produce digital brain endocasts of early hominins at high resolution. Furthermore, medical imaging can now observe the activated cerebral regions of conscious living humans engaged in various tasks or mere thoughts, thus demonstrating the correlation between these regions and specific actions or mental activity. Thus, the cognitive regions activated during the manufacture of stone tools in modern humans implies that these neural structures were either in development or already formed during Lower Palaeolithic tool-making.
This thesis takes the first comprehensive approach to the study of hominin cognitive development, through the contextualised reassessment of hominin crania/endocasts, in concert with hominin manufactured stone tools. The synthesised evidence herein establishes how changes in hominin behaviour, driven by climate and environmental change, generated post-cranial adaptations which, in turn, resulted in neural adaptations, thereby contributing to the evolution of the brain. The evidence suggests that this likely occurred in a mosaic fashion, perhaps as early as the latter australopithecines. It is also likely that the cognitive advancement of these neural structures and the acquisition of new behaviours had a concomitant effect on one another.
Continued work would benefit from a collaboration between the stone tool specialists and palaeo-neurologists, as well as public access to the digital endocast files.