“Culture was once thought to be a particularly human trait. But careful observation of apes demonstrated that they have culture, too. Before culture, tool use was considered a distinctively human capacity. Again, merely watching other creatures shows that this is not the case. One of the last refuges of the species exceptionalist is language, and indeed, human language does seem to be unique. What remains controversial is this: Does our use of language stem from some innate mental capacity that only humans possess?”