Research: Mackenzie's dissertation questions the nature of traditional childhood play among western plains indigenous groups and how play changed in response to colonization. To do this he is re-examining thousands of stone circle site maps and photographs from across the states of Wyoming, Montana, and South Dakota to identify play-related circular features that may have been overlooked in the initial investigations. In addition he uses archival research to investigate how indigenous children played in boarding school contexts based on the words of the children themselves.