Egocentric Bias

Who first named this

Michael Ross & Fiore Sicoly, 1979 — Egocentric Biases in Availability and Attribution

The counsel

Two complementary mechanisms are proposed. (1) Differential availability (Ross & Sicoly, 1979): one's own contributions, thoughts, and efforts are encoded and recalled more easily than others', so when reconstructing a shared event the self looms larger. (2) Egocentric anchoring-and-adjustment (Epley et al., 2004): when judging others, people anchor on their own perspective and adjust insufficiently, which is why the bias grows under time pressure and shrinks with accuracy incentives. Group-size moderation (Schroeder et al., 2016) follows directly: larger groups supply more others' contributions to overlook, so summed over-claiming increases.

Some treat egocentric over-claiming as partly motivational (self-enhancement / self-serving) rather than purely cognitive-availability driven; Ross & Sicoly themselves noted self-presentation cannot fully explain results because the bias persisted for negative outcomes (attenuated, not reversed). Whether the core driver is availability, anchoring, or motivated reasoning remains debated, and the accounts are not mutually exclusive.

The evidence answers

• Each spouse claimed more responsibility than the partner attributed to them; combined self-claimed responsibility exceeded the logical 100% ceiling. The bias appeared for both positive and (attenuated) negative activities.

  Michael Ross, Fiore Sicoly, 1979 · Combined self-attributed responsibility M ~= 103.1% (figure as reported in the 1979 paper and cited by Schroeder, Caruso & Epley, 2016) · Married couples (Experiment 1 of five experiments; exact n not confirmed from retrieved text)

• Replicated over-claiming; prompting people to consider others' contributions reduced self-allocations but, in cooperative groups, left high contributors less satisfied and less interested in future collaboration — a 'cost' of debiasing.

  Eugene M. Caruso, Nicholas Epley, Max H. Bazerman, 2006 · not reported (specific d/eta-squared not confirmed from retrieved text) · Co-authors of published OB articles (Study 1) plus three lab experiments

• Self-claimed responsibility rose with group size (more collaborators to overlook); explicitly considering others' contributions reduced over-claiming. A manipulation that focused attention on self produced summed responsibility M = 122.8% (SD = 29.5%) versus lower in other-focused conditions.

  Juliana Schroeder, Eugene M. Caruso, Nicholas Epley, 2016 · Group-size effect beta = 0.19, p < .001; self-focus vs combined other conditions t(74) = 3.21, p < .01, d = 0.75 · Field study 2: 699 MBA students; plus co-authorship field data and two lab experiments

• Estimates of others' perceptions started from the self and adjusted serially; egocentric bias increased under time pressure and decreased with accuracy incentives, supporting an anchoring-and-adjustment mechanism.

  Nicholas Epley, Boaz Keysar, Leaf Van Boven, Thomas Gilovich, 2004 · not reported (specific effect sizes not confirmed from retrieved text) · Five studies (sample sizes not confirmed from retrieved text)

The record

Egocentric bias is the documented tendency to anchor judgments of shared events on one's own perspective and more-available memories, leading people to claim more responsibility for joint outcomes than is logically possible. Michael Ross and Fiore Sicoly established it experimentally in 1979 across couples, sports teams, and lab groups; the signature finding is that summed self-attributed responsibility exceeds 100% (about 103% for married couples). Later work (Caruso/Epley/Bazerman 2006; Schroeder/Caruso/Epley 2016) replicated the effect and showed over-claiming grows with group size, while the mechanism is best understood as egocentric anchoring-and-adjustment plus differential availability of self-relevant information.