Social comparison plays an important role in our daily life. Several studies have investigated the neural mechanism of social comparison; however, their conclusions remain controversial. The present study explored the neural correlates of intelligence comparison and nonsocial size comparison using functional magnetic resonance imaging and a distance effect paradigm. We found that both intelligence and size comparisons obeyed the behavioral distance effect-longer response times for near than far distances and this effect involved an overlapping frontal network including the dorsomedial prefrontal cortex and insula. In addition, compared with size comparisons, intelligence comparisons elicited increased activity in the precuneus and angular gyrus, but decreased activity in the inferior parietal lobe. Furthermore, the analysis of seed-based functional connectivity complemented these neural commonalities and differences. Our findings suggest that social and nonsocial comparisons may rely on a common core mechanism, but this mechanism may be supplemented by different domain-specific cognitive components.