The measurement, evolution, and neural representation of action grammars of human behavior

• Published in: Scientific reports Vol. 11; no. 1; pp. 13720 - 13
• Main Authors: Stout, Dietrich, Chaminade, Thierry, Apel, Jan, Shafti, Ali, Faisal, A. Aldo
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 02.07.2021; Nature Publishing Group; Nature Portfolio
• Subjects: 631/181/27; 631/378/2649; 631/477/2811; Algorithms; Archaeology; Behavior; Behavioral Research - methods; Biological anthropology; Biological Evolution; Brain - diagnostic imaging; Brain - physiology; Brain mapping; Brain research; Coevolution; Cognition; Cognition & reasoning; Cognitive science; Evolution; Functional magnetic resonance imaging; Humanities and Social Sciences; Humans; Language; Magnetic Resonance Imaging; Models, Psychological; multidisciplinary; Neural coding; Neuroscience; Paleolithic; Science; Science (multidisciplinary); Tool Use Behavior - physiology
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-021-92992-5

Human behaviors from toolmaking to language are thought to rely on a uniquely evolved capacity for hierarchical action sequencing. Testing this idea will require objective, generalizable methods for measuring the structural complexity of real-world behavior. Here we present a data-driven approach for extracting action grammars from basic ethograms, exemplified with respect to the evolutionarily relevant behavior of stone toolmaking. We analyzed sequences from the experimental replication of ~ 2.5 Mya Oldowan vs. ~ 0.5 Mya Acheulean tools, finding that, while using the same “alphabet” of elementary actions, Acheulean sequences are quantifiably more complex and Oldowan grammars are a subset of Acheulean grammars. We illustrate the utility of our complexity measures by re-analyzing data from an fMRI study of stone toolmaking to identify brain responses to structural complexity. Beyond specific implications regarding the co-evolution of language and technology, this exercise illustrates the general applicability of our method to investigate naturalistic human behavior and cognition.