Birds of a feather flock together: Evidence of prominent correlations within but not between self-report, behavioral, and electrophysiological measures of impulsivity.

Despite many studies examining a combination of self-report, behavioral, and neurophysiological measures, only few address whether these different levels of measurement indeed reflect one construct. The present study aids in filling this gap by exploring the association between self-report, behavioral, and electrophysiological measures of impulsivity and related constructs such as sensation seeking, reward responsiveness, and ADHD symptoms. Individuals across two large samples (n = 133 and n = 142) completed questionnaires and performed behavioral tasks (the Eriksen Flanker task, the Go/No-Go task, the Reward task, and the Balloon Analogue Risk Task) during which brain activity was measured using electroencephalography (EEG). The resulting data showed that even though the correlations within each level of measurement were prominent, there was no evidence of significant correlations across the three measurement levels. These findings contradict the outcomes of some previous, smaller studies, which did report significant associations between self-reported impulsivity(-related) measures and behavior and/or electrophysiology. Therefore, we suggest using sufficiently large samples when investigating associations between different levels of measurement.