Lithic industries, modern tools, and language: An evolutionary perspective through fMRI

Area of Science:

• Neuroscience
• Cognitive Science
• Archaeology

Background:

• Tool use is a hallmark of human cognition, underpinned by technical reasoning.
• Neuroarchaeological evidence suggests a frontoparietal network for lithic tool use, evolving into the modern tool network.
• The left inferior frontal gyrus's involvement in both tool use and language suggests co-evolution, potentially due to hierarchical structuring.

Purpose of the Study:

• To investigate how mechanical complexity affects frontoparietal activity during tool evaluation.
• To determine if lithic and modern tools engage a common neural network.
• To explore the neurocognitive basis of technical reasoning and its relation to language evolution.

Main Methods:

• Functional magnetic resonance imaging (fMRI) was used to monitor brain activity.
• Participants evaluated the functionality of lithic and modern tools across three complexity levels.
• Functional connectivity between specific brain regions (left PF and left pars opercularis) was analyzed.

Main Results:

• Increased mechanical complexity led to stronger functional connectivity between the left area PF and the left pars opercularis.
• Both lithic and modern tools activated a common neural network.
• Frontoparietal connectivity was found to scale with the complexity of tool evaluation.

Conclusions:

• Frontoparietal brain network connectivity dynamically adjusts with the mechanical complexity of tools.
• A shared neural network supports the evaluation of both ancient and modern tools.
• Hierarchical processing may be a fundamental computational principle underlying the co-evolution of tool use and language.