Human thought is shaped by our interactions with other people, as well as our interactions with the products of people: cultural artifacts, technologies, and repertoires of information. By building upon each other's discoveries and behaviors over time and across cultures, humans create vast systems of knowledge that we pass on to subsequent generations. Scientist Cristine Legare's research at The University of Texas at Austin illuminates how the near-absence of cumulative culture in other species suggests humans are unique among animals. Her research team is examining why humans have developed sophisticated technology over time, while chimpanzees — our closest primate relative — have been using and continue to use primitive tools over the same span of time.