Librarians insist that one of the ways they can contribute to the fight against mis-and disinformation is by teaching information literacy. Yet the demands they place on individuals-- whether through lengthy checklists or expectations that individuals interrogate every piece of information encountered--are unrealistic in view of information processing research. The human default is not systematic but heuristic evaluation, relying on computational shortcuts for decision making. Moreover, these demands may be unnecessary and unrepresentative of what librarians do, given research showing that experts often rely on less information than expected when arriving at decisions, particularly in real-world settings. There are even situations in which relying on less information leads to better outcomes. Drawing on interdisciplinary research on credibility, heuristics, expertise, and information processing, this dissertation investigates how librarians evaluate political news articles across three studies. Study 1 tests the reliance on non-content source cues on evaluative judgments. Study 2 comprises a series of observational interviews as librarians evaluate news stories, focusing on cognitive rather than behavioral components of their evaluations. Study 3 extends and tests the findings from the interviews through a larger experiment aimed at determining the evaluation strategies and criteria librarians use when evaluating articles. The findings suggest that librarians rely on only a few strategies or criteria, some of which are heuristic, but that those strategies vary dynamically depending on the source, article content, and librarians' prior knowledge of and pre-existing views on the topic. Equally important are the skills and habits acquired through experience. These results have implications for contemporary discussions of information and media literacy and highlight the need for library and information science to engage more critically with research outside the field. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]