What is the relationship between magnitude judgments relying on directly available characteristics versus probabilistic cues? Question frame was manipulated in a comparative judgment task previously assumed to involve inference across a probabilistic mental model (e.g., “Which city is largest”—the “larger” question—vs. “Which city is smallest”—the “smaller” question). Participants identified either the largest or smallest city (Experiments 1a and 2) or the richest or poorest person (Experiment 1b) in a 3-alternative forced-choice (3-AFC) task (Experiment 1) or a 2-AFC task (Experiment 2). Response times revealed an interaction between question frame and the number of options recognized. When participants were asked the smaller question, response times were shorter when none of the options were recognized. The opposite pattern was found when participants were asked the larger question: response time was shorter when all options were recognized. These task–stimuli congruity results in judgment under uncertainty are consistent with, and predicted by, theories of magnitude comparison, which make use of deductive inferences from declarative knowledge.