Social comparison and handedness: Mixed-handers are less susceptible to egocentric biases in judgments about others' performance

Abstract

Prior research has shown that, relative to mixed/inconsistent-handers, strong/consistent-handers show a stronger Dunning-Kruger effect in social comparison, in which people overestimate their performance on easy tasks and underestimate their performance on difficult tasks. However, this earlier study did not include actual performance measures, leading to the possibility that the effects may have reflected actual handedness differences in performance. In the current study, strong/consistent- and mixed/inconsistent-handers answered a set of either easy or difficult trivia questions and then provided estimates of their own versus others' level of performance. Consistent with the Dunning-Kruger effect in social comparison, strong/consistent-handers overestimated their performance on the easy questions and underestimated their performance on the difficult questions. This effect was significantly attenuated in mixed/inconsistent-handers. Results are interpreted in terms of mixed/inconsistent-handers having greater access to right hemisphere areas involved in perspective taking.