<p>Social, dimensional, and temporal comparisons are important influencing factors of academic self-concepts. Typical consequences of these comparisons are assimilation and contrast effects, in which students adjust their self-assessment in subject-specific abilities closer to a comparison standard (assimilation) or further away from a comparison standard (contrast). However, the psychological mechanisms underlying these effects in social, dimensional, and temporal comparisons have largely been neglected in research so far. Therefore, the present study addresses this research gap using a reaction time experiment. A total of <i>N</i> = 586 students (ninth and tenth grade) were primed with similar or dissimilar social, dimensional, or temporal comparison standards. Following, they were asked to classify two symbols as unequal or equal as fast as possible. Based on the selective accessibility model, we expected that differences between reaction times to unequal and equal symbols following similar comparisons (similar comparison standards) should differ significantly from differences between reaction times to unequal and equal symbols following dissimilar comparisons (dissimilar comparison standards), due to a similarity focus accompanying similar comparisons and a dissimilarity focus accompanying dissimilar comparisons. However, despite a high power of our study, we found no significant differences in the reaction time differences for any comparison type. These findings do not imply that social, dimensional, and temporal comparisons in academic self-concept formation are accompanied by similarity and dissimilarity foci depending on the similarity of the comparison standard.</p>