When making inferences about similar others, people anchor and adjust away from themselves (Tamir & Mitchell, 2013). However, research on relational self theory (Andersen & Chen, 2002) suggests the possibility of using knowledge about others as an anchor when they are more similar to a target. We investigated whether social inferences are made on the basis of significant other knowledge through an anchoring and adjustment process, and whether anchoring on a significant other is more effortful than anchoring on the self. Participants answered questions about their likes and habits, as well as the likes and habits of a significant other, a target similar to their significant other, and a yoked control. We found that prediction differences between the significant other and similar target led to longer response times, and we found the opposite effect for self and target differences, suggesting anchoring and adjustment from the significant other rather than the self. These effects were moderated by the source‐relative salience of the dimension being evaluated. The evidence was mixed with respect to the question of whether anchoring on a significant other is more effortful than anchoring on the self.