so -- >> hi i am gregory walsh. i have been looking forward to reading the book since seeing a speech you gave 3-4 years ago at the ted conference on this topic. i was wondering, however, if you could comment on allegations made in a book i recently read called sex at dawn the prehistoric origins of modern sexuality in which the author presents the data you present about the rates of violence among hunter and gather cultures, non-state people is erroneous and they allege for example that the data at the time it was collected these people had contact with modern society for many decades and that they are not in fact nomadic. they are settled people. i have been curious since reading that to hear your response to allegations. >> i am not familiar with the allegation allegations. but the data i present are from people who definitely had no contact with any europeans like samples of skeletons from pre-columbian native americans. many are from hunter gathering people who had no contact as well no contact. the sources i c