This chapter focuses on micro encounters engendered by the Yale Peruvian Expedition, exploring via textual and photographic evidence the racial scientific research that shaped encounters in Peru between expedition members and Indigenous and Mestizo peoples, some of whom served as the expedition’s workers and assistants. Reading these sources in relation to the broader context of rural unrest in the Cusco region, the emergence of an urban and university-based indigenista movement that promoted the study of Indigenous peoples, and the rise of American-led expedition science, Warren questions how different groups imagined and contested the moral and ethical dimensions of such work. He argues that when measured and photographed, Indigenous and Mestizo research subjects ultimately subverted the expedition’s efforts to document accurate visual depictions of racial types. Drawing on the concept of ethnographic refusal in Indigenous Studies while also identifying other forms of engagement, Warren criticizes the univocal conception of moral fields as the possession of imperial researchers but not of Indigenous and Mestizo people subjected to their gaze.