Stone Tool-Making and Brain Activation: Position Emission Tomography (PET) Studies

This study introduces to archaeology a new experimental technique for examining the relationship between stone tool-making and brain function. The principal focus of this exploratory study was the development of effective methods for the identification and examination of the regions of the modern human brain recruited during the manufacture of simple (Oldowan or Mode I) stone tools. The functional brain imaging technique employed, Positron Emission Tomography (PET), examines task-related brain activity by assessing changes in regional cerebral blood flow during specific tasks. The single-subject study reported here represents a heuristic, initial exploration of this subject. Results indicate that during stone tool-making there was heavy activation of cortical and subcortical regions of the brain associated with motor and somatosensory processing. Especially interesting was the high degree of activation in areas known to be involved with complex spatial cognition requiring integration of diverse sensory inputs (e.g. vision, touch, and proprioception, or sense of body position and motion). Expansion of such higher-order association areas has been particularly important during the course of human evolution. This single-subject pilot study demonstrates the application of the PET brain imaging technique to the study of early stone technologies and suggests hypotheses to be tested in more comprehensive studies in the future.