Such techniques were also integral to Maria Montessori's methods in the twentieth century. According to Cleverley and Phillips, the television show Sesame Street is also "based on Lockean assumptions—its aim has been to give underprivileged children, especially in the inner cities, the simple ideas and basic experiences that their environment normally does not provide." In many ways, despite Locke's continuing influence, as these authors point out, the twentieth century has been dominated by the "nature vs. nurture" debate in a way that Locke's century was not. Locke's optimistic "environmentalism," though qualified in his text, is now no longer just a moral issue – it is also a scientific issue.