The article introduces neuroscience methods in HRD through a study that highlights the role of reflection in developing leaders. Despite increased attention on neuroscience discoveries and its methodologies in the social sciences, there is limited research among HRD scholars that incorporates neuroscience approaches. Relatedly, HRD practitioners and scholars often view reflection as a critical element for developing human resources and leaders. Yet, there is a dearth of research that focuses on the impact of reflection in the brain and the underlying neurocognitive mechanisms that support it. The purpose of this paper is to neurobiologically examine how individual or collective reflection impacts leaders' frontal lobe brain activities during challenging situations, incorporating electroencephalography (EEG) as a method. The paper concludes with suggestions for future research and practical implications. [ABSTRACT FROM AUTHOR]