The habit of bringing home unusual stones and old tools may have helped human ancestors develop memory and self-awareness. Researchers Ran Barkai and Yoav Ram of Tel Aviv University reached this conclusion while studying finds from the Levant, infohub.kz reports.
The scientists focused on objects that ancient people brought to their campsites with no obvious practical purpose. In Kesem Cave, people collected small multicolored pebbles over a period of 200,000 years, while in the Sahnin Valley they made hand axes from flint that was difficult to work, deliberately leaving imprints of ancient fossils in the center of the tool.
In addition, at the Revadim and Jaljulia sites, archaeologists found old stone tools covered in patina — the natural film of time. Ancient craftsmen resharpened their edges but left the old surface untouched. Microscopic analysis showed that the refurbished tools were almost never used for work. The scientists believe such objects served as "memory objects" and reminded their owner of a specific event or place.
According to the study's authors, the habit of keeping mementos emerged around 400,000 years ago, when elephants disappeared from the region and people had to move into new territories to hunt smaller prey. The mementos worked as "external memory devices": they helped the brain distinguish real memories from imagination and laid the foundation for the development of autobiographical memory.