article_snippet: Towards the end of this period, tools became more refined and then followed the so-called Levallois technique, which saw the creation of scrapers, slicers, needled and flattened needles.
article_snippet: As human culture advanced, artefacts such as fish hooks, buttons and bone needles were used.
article_snippet: One of the key pieces of evidence for human tool making is a characteristic bulge or dent on the surface of a stone known as a bulb of percussion.
article_snippet: The researchers looked in - ranging from large flakes knocked off boulders that were used for cutting to sophisticated stone shapes.
article_snippet: The researchers found evidence that specific tools had been used to wedge into pieces of stone to help slit it in certain ways.
article_snippet: Scientists looked for bulges or dents on the surface of stones, like above, for signs of human modification .