Positive emotions and inhibitory control enhance prosocial sharing behavior in children under unequal resource conditions: An fNIRS study

Prosocial sharing in unequal contexts is a core issue in children's moral and social development, but the underlying neural mechanisms and the role of emotion regulation and inhibitory control of cognitive structures in them remain under-explored. Leveraging the portability of functional near-infrared spectroscopy (fNIRS), this study measured prefrontal cortex oxyhemoglobin changes during sharing behaviors in children aged 6–9 under unequal resource conditions, and explored the contributions of emotion and cognitive regulation mechanisms. The results showed: (1) Children's sharing behavior significantly increased with age and varied across resource statuses; (2) Children with stronger inhibitory control and higher positive emotions showed greater prosocial tendencies; (3) In disadvantaged conditions, left dorsolateral prefrontal cortex (dlPFC) showed greater increase in HbO concentration than advantaged conditions. At the same time, children aged 8 to 9 also show significant differences in the left medial prefrontal cortex (mPFC) between different conditions; (4) Task-based functional connectivity analysis indicated that children aged 8–9 exhibited stronger connectivity in the right and left dorsolateral prefrontal cortices compared to their counterparts aged 6–7, as well as stronger connectivity in the bilateral medial prefrontal cortices. Moreover, the exploratory analysis revealed that the HbO concentration in the right dlPFC under disadvantageous conditions positively correlated with sharing behavior, while the HbO concentration in the left medial prefrontal cortex negatively correlated with sharing behavior in advantage conditions. In summary, this study provides the important neuroimaging evidence revealing that children's prosocial decision-making in unequal scenarios is jointly influenced by cognitive control and emotional assessment.