Closer the relatives are, more intimate and similar we are: Kinship effects on self-other overlap

• We explored the influence of kinship on self-others overlap.
• The closer blood relationship, the more self-relatives overlap.
• Social interactions moderates the effect of proximity of blood relationship.
• Social interactions are a more significant influential factor.

This study examined the degree of self-other overlap among relatives. We hypothesize that the proximity of blood relationship and the closeness of social interactions are two factors that tend to increase self-other overlap. Participants evaluated their self-other overlap with various blood relatives. The target people were generated by a 3 (lineal relatives, collateral relatives, and remote relatives) × 2 (close/distant social interactions) design. Participants identified each target person from blood relatives they knew personally. The IOS scale, the Dynamic IOS scale, and the absolute difference in personality attribute ratings were used to measure self-other overlap. The results indicated that closer blood relations were associated with greater self-other overlap, and that experience of social interactions increased the self-other overlap.