Appeals built on shared identity outperform appeals to mere similarity.
Cialdini added it as the seventh principle in 2016. Shared identity — family, region, faith — outperforms mere similarity because it invokes being of the same category rather than being alike.
In practice
- A fundraising letter opening "as a fellow parishioner" outperforms one opening "as someone who also enjoys gardening".
- A recruiter who shares a home town with a candidate gets a reply where four identically worded approaches did not.