The evolution of self-control

TLDR

Scientists have identified surprising cognitive flexibility in animals and unique features of human psychology, yet little is known about the selective forces that favor cognitive evolution or the proximate biological mechanisms underlying this process. The study aimed to test 36 species in two problem‑solving tasks measuring self‑control and evaluate leading hypotheses about cognition evolution. The authors employed two problem‑solving tasks across 36 species to assess self‑control and test hypotheses regarding how and why cognition evolves. Absolute brain volume best predicted performance on the tasks, and within primates dietary breadth predicted cognitive performance while social group size did not, indicating that increases in absolute brain size provide the biological foundation for evolutionary increases in self‑control and that feeding ecology may be a selective pressure.

Abstract

Significance Although scientists have identified surprising cognitive flexibility in animals and potentially unique features of human psychology, we know less about the selective forces that favor cognitive evolution, or the proximate biological mechanisms underlying this process. We tested 36 species in two problem-solving tasks measuring self-control and evaluated the leading hypotheses regarding how and why cognition evolves. Across species, differences in absolute (not relative) brain volume best predicted performance on these tasks. Within primates, dietary breadth also predicted cognitive performance, whereas social group size did not. These results suggest that increases in absolute brain size provided the biological foundation for evolutionary increases in self-control, and implicate species differences in feeding ecology as a potential selective pressure favoring these skills.