News release

From: The Royal Society

Social cues on stone tools outweigh raw material properties in wild primates

This study uncovers how different cues influence how capuchin monkeys choose stone tools for cracking nuts. Researchers gave two groups of monkeys nut-cracking tasks using stones that differed in quality and signs of prior use. When stones were unused, monkeys chose tools based on hardness. However, when stones showed wear from previous nut-cracking, monkeys preferred those—regardless of their hardness. This work shows that capuchins can favor social cues created by the previous use of the tools by others. The findings highlight how socially embedded information sharing may shape the development of tool use, offering insights into the evolution of our own technology.