The ability of ancient humans to master tools coincided with their ability to teach others, a new study says. UK researchers conducted experiments designed to replicate the evolution of human-made tools over several hundred years with pipe cleaners and bits of paper. The experts found that participants who taught each other made the most rapid progress, compared with those who had to merely imitate others or learn by themselves. The improvement of technologies and tools across generations, known as'cumulative cultural evolution' (CCE), has been key to our success as a species. But the origins of CCE, which have led to world-changing inventions such as the internet, aviation and human spaceflight, are difficult to trace.