Unrealistic optimism is a tendency of people to see their own chances to be above average for positive events and below average for negative events. These effects are often regarded as products of motivated reasoning. Recently however the nonmotivated accounts of comparative biases are more popular. The present paper discusses the existing cognitive explanations of the mechanisms underlying the biases in the comparative judgments. First, the authoress briefly reviews motivational accounts of comparative biases. Then there are presented the most popular nonmotivated accounts: egocentrism, focalism and LOGE approach. Finally, the article discusses an alternative explanation of biased comparative judgments that stems from the feature matching model of Tversky (1977).