Agroundbreaking new study has opened the book on chimpanzee culture and its transmission, revealing compelling evidence that it is cumulative and spreads through social groups over generations. Using what they’re calling a “genetic time machine,” scientists have peered back into thousands of years’ worth of gene transfer, and spotted patterns between migrating females and the emergence of some of their most advanced examples of tool use. This demonstrates that advanced techniques don’t pop up randomly, but instead spread between social groups, gaining further reach over several generations.