This is a Lexicon entry: the mechanism, when it shows up, and the countermeasure. The full correction, with real-world cases and the audit prompt, hasn't been written yet.
When it shows up
Joint projects where each collaborator estimates their contribution at 60-70%. Married couples who each believe they do more than half the housework. Teams where every member thinks they carried the group. Memory for shared conversations is systematically biased toward one's own statements.
Failure mode
Resentment in partnerships from perceived unequal contribution. Overvaluing your own ideas in group settings. Failing to credit others adequately. In negotiations, each side genuinely believes they are making larger concessions.
Countermeasure
Ask each party to estimate contributions independently, then compare. The total will exceed 100%, revealing the bias. For decisions: actively seek others' perspectives before forming your own. Apply CL-7 (Steel Man).
Related traps
Also connected in the mapSelf-serving Bias·The Illusion of Transparency·4 more, locked
Read next
Entry #93 of 631 in The Lexicon · see the full Lexicon