Major transitions in the physiological machinery of cognition

Cognition refers to the processes organisms use to interact with and understand their world, a fundamental biological function present in all cellular life. As with any biological process, cognitive capacity and its underlying mechanisms vary widely across species. Evolution has shaped cognition, leading to increasingly complex forms in certain lineages. The concept of evolutionary transitions, introduced by Maynard-Smith and Szathmary, describes major shifts in biological organization. In 2021, Ginsburg & Jablonka, and in 2023, Barron and collaborators explored cognitive transitions within neural systems, the evolution of cognition in aneural organisms remains understudied. Building on prior frameworks, we analyze cognitive transitions in the aneural realm, focusing on the physiological machinery responsible for cognition. The first transition is the emergence of cognitive machinery in prokaryotic cells (cellular cognition), followed by its complexification in eukaryotes (complex cellular cognition). The third transition marks cognition based on multiple cells (multicellular-based cognition). The fourth is the development of neurons and a diffuse nervous system (decentralized neural cognition), followed by its centralization (brain cognition). The sixth transition involves advanced brain architectures enabling complex cognition (complex brain cognition). The final transition is the emergence of human cognition, supported by symbols and culture (cultural-linguistic cognition). This hierarchical framework captures the increasing complexity of cognitive machinery across evolutionary transitions. By incorporating aneural cognition, we provide a more comprehensive view of the diversity of cognitive systems in nature.