Chambers, J. R., & Windschitl, P. D. (2004). Biases in social comparative judgments: The role of nonmotivated factors in above-average and comparative-optimism effects. Psychological Bulletin, 130, 813-838.

People often hold unwarranted beliefs that they are better than others and are more likely to experience positive and avoid negative events. Biases in social comparative judgments, such as those illustrated by above-average effects and comparative-optimism effects, are often regarded as a product of some form of motivation (e.g., self-enhancement). These effects, however, can also be produced by information-processing limitations or aspects of judgment processes that are not necessarily biased by motivational factors. In this paper, we first briefly review motivational accounts of biased comparative judgments. Then we introduce a 3-stage model for understanding how people make comparative judgments, and we describe how various nonmotivational factors can influence the evidence-recruitment, absolute-evaluation, and comparative-judgment-formation stages of the model. Finally, we discuss several unresolved issues highlighted by our analysis, such as the interrelation between motivated and nonmotivated sources of bias and the influence of nonmotivated sources of bias on behavior.