This study details the design of library instruction sessions for undergraduate students that intended to encourage critical source evaluation and the questioning of established authorities, and appraises these instructional aims through a thematic analysis of 148 artifacts containing student responses to group and individual activities. The authors found a widespread reliance on traditional indicators of academic and scholarly authority, though some students expressed more personal or complex understandings of source evaluation, trustworthiness, and authorship. Based on the findings, recommendations are made for academic librarians interested in promoting learners' senses of agency and authority.