how connection developsBeing alike and believing we are alike are different experiences. Montoya, Horton and Kirchner examined that distinction across 313 investigations of interpersonal attraction.
Actual similarity concerned shared attributes. Perceived similarity concerned how alike people believed themselves to be. Both were associated with attraction overall, but the pattern changed across interaction settings.
Actual similarity had its strongest association with attraction when people evaluated someone without interacting. The association was smaller after brief contact and was not statistically significant in established relationships. Perceived similarity remained associated with attraction across all three settings.
These comparisons concern different studies, rather than demonstrating that similarity loses importance as any particular relationship develops. The authors also considered influence in both directions. Feeling similar may encourage attraction, while liking someone may encourage an impression of similarity.
Their findings distinguish the characteristics people share from the common ground they experience within a relationship.
Sources
Montoya, R. M., Horton, R. S., & Kirchner, J. (2008). Is actual similarity necessary for attraction? A meta-analysis of actual and perceived similarity. Journal of Social and Personal Relationships, 25(6), 889–922.