Our results show a significant and robust decrease of ERO theta power with age, presumably reflecting developmental changes in the neural mechanisms of outcome monitoring (Fig 3 Panels C1 and C2). This finding is in line with well-known developmental reduction of P3 amplitude [166,167] and resting EEG power [168–174]. In error monitoring paradigms, the error-related P3 amplitude (“error positivity”) decreased with age [175], in contrast to the error-related negativity (ERN) that showed a significant increase from 7 to 17 years of age [176]. Although there have been no reward related ERO findings reported between different age groups, Hammerer et al. [177] measured the FRN in children, adolescents, younger adults, and older adults, and found that the amplitude of the FRN after gains and losses decreased monotonically from childhood to old age. These developmental changes could be due to dopaminergic and prefrontal contributions to reward-based learning and outcome monitoring across development from childhood to old age [177,178], and may also reflect changes associated with the salience of reward information as well as the declining ability to monitor and control behavior across
