The ability to critically evaluate whether information presented actually supports a given claim is essential for cognitive and social development. This paper presents a study focusing on developmental and contextual aspects of this ability (called antilogos). We tested antilogos for different variables: age group (Grades 8 and 10), direction of information (one text was presented as supporting a claim and the other was presented as opposing the same claim), whether or not a personal argument is constructed before critical evaluation, and whether or not a worked-out example is provided before critical evaluation. The study indicates that (a) antilogos develops during adolescence; (b) it differs for different directions of information; (c) the combination of expressing personal argument before critical evaluation and being provided a worked-out example improves antilogos performance in Grade 8 students; and (d) personal standpoint can be neutralized during critical evaluation. Important educational lessons are drawn from the study.