 A second group of constructionist claims emphasizes personal social agents that construct through their choices. For example, Andrew Pickering’s (1984) influential work Constructing Quarks emphasizes the role of scientists’ judgments in a variety of roles in scientific process including, e.g., theory selection, experiment evaluation, assessments of research fecundity, and so forth, and such an emphasis on apparently highly contingent choices by researchers and scientific institutions is a mainstay of the social studies of knowledge literature. In emphasizing personal choices, some constructionist work (including some of Pickering’s) seems primarily aimed at emphasizing the contingency of the scientific theory that we come to accept (cf. Hacking  1999).[2]  Other constructionists—those we might call critical constructionists—emphasize personal choices not just to establish the contingency of the acceptance of some representation as to emphasize the role of an agent’s interests or power relations in determining the content of an accepted representation. For example, Charles Mills suggests that the borders of American racial categories were determined in such a way as to “establish and maintain the privileges of different groups. So, for example, the motivation for using the one-drop rule to determine black racial membership is to maintain the subordination of the products of ‘miscegenation’” (1998, 48). And a range of constructionist research, especially research on human classifications like “race” and “gender,” documents shifts in human classification in response to shifts of interests or power.