On the Neurocognitive Co-Evolution of Tool Behavior and Language: Insights from the Massive Redeployment Framework.

Understanding the link between brain evolution and the evolution of distinctive features of modern human cognition is a fundamental challenge. A still unresolved question concerns the co-evolution of tool behavior (i.e., tool use or tool making) and language. The shared neurocognitive processes hypothesis suggests that the emergence of the combinatorial component of language skills within the frontal lobe/Broca's area made possible the complexification of tool-making skills. The importance of the frontal lobe/Broca's area in tool behavior is somewhat surprising with regard to the literature on neuropsychology and cognitive neuroscience, which has instead stressed the critical role of the left inferior parietal lobe. Therefore, to be complete, any version of the shared neurocognitive processes hypothesis needs to integrate the potential interactions between the frontal lobe/Broca's area and the left inferior parietal lobe as well as their co-evolution at a phylogenetic level. Here, we sought to provide the first elements of answer through the use of the massive deployment framework, which posits that evolutionarily older brain areas are deployed in more cognitive functions (i.e., they are less specific). We focused on the left parietal cortex, and particularly the left areas PF, PGI, and anterior intraparietal (AIP), which are known to be involved in tool use, language, and motor control, respectively. The deployment of each brain area in different cognitive functions was measured by conducting a meta-analysis of neuroimaging studies. Our results confirmed the pattern of specificity for each brain area and also showed that the left area PGI was far less specific than the left areas PF and AIP. From these findings, we discuss the different evolutionary scenarios depicting the potential co-evolution of the combinatorial and generative components of language and tool behavior in our lineage.

The Pedagogue, the Engineer, and the Friend : From Whom Do We Learn?

Humans can follow different social learning strategies, sometimes oriented toward the models' characteristics (i.e., who-strategies). The goal of the present study was to explore which who-strategy is preferentially followed in the technological context based on the models' psychological characteristics. We identified three potential who-strategies: Copy the pedagogue (a model with high theory-of-mind skills), copy the engineer (a model with high technical-reasoning skills), and copy the friend (a model with high level of prosocialness). We developed a closed-group micro-society paradigm in which participants had to build the highest possible towers. Participants began with an individual building phase. Then, they were gathered to discuss the best solutions to increase tower height. After this discussion phase, they had to make a new building attempt, followed by another discussion phase, and so forth for a total of six building phases and five discussion rounds. This methodology allowed us to create an attraction score for each participant (the more an individual was copied in a group, the greater the attraction score). We also assessed participants' theory-of-mind skills, technical-reasoning skills, and prosocialness to predict participants' attraction scores based on these measures. Results show that we learn from engineers (high technical-reasoning skills) because they are the most successful. Their attraction power is not immediate, but after they have been identified as attractors, their technique is copied irrespective of their pedagogy (theory-of-mind skills) or friendliness (prosocialness). These findings open avenues for the study of the cognitive bases of human technological culture.