New research shows that blood flow patterns to the brain in the first 10 seconds of initiating tool making correlate with the patterns when using language. The conclusion being drawn is not only that the same areas of the brain are involved but also that tool-making and language probably evolved together.
Tool making probably began some 2.6 million years ago and certainly our ancestors had the physiological basis for speech at least 500,000 years ago. The earliest words must however have come very much earlier.
Natalie Thaïs Uomini and Georg Friedrich Meyer, Shared Brain Lateralization Patterns in Language and Acheulean Stone Tool Production: A Functional Transcranial Doppler Ultrasound Study, PLoS ONE, 2013; 8 (8): e72693 DOI: 10.1371/journal.pone.0072693
Abstract: The popular theory that complex tool-making and language co-evolved in the human lineage rests on the hypothesis that both skills share underlying brain processes and systems. However, language and stone tool-making have so far only been studied separately using a range of neuroimaging techniques and diverse paradigms.
We present the first-ever study of brain activation that directly compares active Acheulean tool-making and language. Using functional transcranial Doppler ultrasonography (fTCD), we measured brain blood flow lateralization patterns (hemodynamics) in subjects who performed two tasks designed to isolate the planning component of Acheulean stone tool-making and cued word generation as a language task. We show highly correlated hemodynamics in the initial 10 seconds of task execution.
Stone tool-making and cued word generation cause common cerebral blood flow lateralization signatures in our participants. This is consistent with a shared neural substrate for prehistoric stone tool-making and language, and is compatible with language evolution theories that posit a co-evolution of language and manual praxis. In turn, our results support the hypothesis that aspects of language might have emerged as early as 1.75 million years ago, with the start of Acheulean technology.
From the University Press Release:
Research by the University of Liverpool has found that the same brain activity is used for language production and making complex tools, supporting the theory that they evolved at the same time.
Researchers from the University tested the brain activity of 10 expert stone tool makers (flint knappers) as they undertook a stone tool-making task and a standard language test.
They measured the brain blood flow activity of the participants as they performed both tasks using functional Transcranial Doppler Ultrasound (fTCD), commonly used in clinical settings to test patients’ language functions after brain damage or before surgery.
The researchers found that brain patterns for both tasks correlated, suggesting that they both use the same area of the brain. Language and stone tool-making are considered to be unique features of humankind that evolved over millions of years.
Darwin was the first to suggest that tool-use and language may have co-evolved, because they both depend on complex planning and the coordination of actions but until now there has been little evidence to support this.
“Our study found correlated blood-flow patterns in the first 10 seconds of undertaking both tasks. This suggests that both tasks depend on common brain areas and is consistent with theories that tool-use and language co-evolved and share common processing networks in the brain.”