Self-Protection and Self-Enhancement Biases in Estimates of Population Prevalence

Abstract

Population prevalence estimates of others' successes and failures at a task were used to assess self-serving biases in response to one's own success and failure. The strength of self-protective motives in reaction to failure feedback and self-enhancing motives in reaction to success feedback was assessed. Large biases based on self-protection motives were observed, in that failure subjects made higher estimates of others' failure and lower estimates of others' success than no-feedback control subjects. Biases based on self-enhancement were observed only for non-depressed subjects. In addition, nondepressed failure subjects showed generalized effects of the self-protection motive, as they evidenced larger false consensus biases than control subjects for task-unrelated attributes and beliefs. Finally, all motivational effects were considerably stronger for nondepressed than for depressed subjects. Implications for processes underlying biases in population prevalence estimates are discussed.