Reliability of reward- and error-related brain activity in early childhood.

Event-related potential (ERP) measures of reward- and error-related brain activity have emerged as potential biomarkers of risk for the development of psychopathology. However, the psychometric properties of reward- and error-related brain activity have been primarily investigated in adolescents and adults. It is critical to also establish the reliability of ERPs in younger children, particularly if they are used as individual difference measures of risk during key developmental periods. The present study examined the reliability of the reward positivity (RewP) and error-related negativity (ERN) among 80 children (M  = 6.9 years old; 50% female). Participants completed the doors, flanker, and go/no-go tasks twice, separated by approximately 8 months, while electroencephalography (EEG) was recorded. Results indicated that the RewP demonstrated strong internal consistency and test-retest reliability. The ERN also demonstrated strong internal consistency, but test-retest reliability was only significant for the ERN measured during the flanker task and not the go/no-go task. These results are largely consistent with reported psychometric properties of reward- and error related ERPs in adolescents and adults, suggesting that the ERN and RewP may be appropriate biomarkers of individual differences in populations ranging from early childhood to adulthood.