Right-lateralized prefrontal signature with successful Stroop-like interference control in early childhood

The Stroop effect is a canonical measure of executive control, yet its neural architecture has been defined largely in literate children and adults, where left frontal mechanisms have long been implicated in resolving verbal conflict. How the developing brain supports Stroop-like interference control before literacy and stable verbal responding are established remains unknown. Here we show that successful interference control in early childhood is associated with the selective engagement of right lateral prefrontal regions. We used multichannel functional near-infrared spectroscopy to measure prefrontal hemodynamics in 94 children aged 35-79 months during a color-pointing Stroop-like task, in which children pointed to colors in response to spoken color names. Stroop-like conflict elicited broad activation across bilateral lateral prefrontal regions, a conflict response already present from around 3 years of age and did not show a detectable age-related increase. By contrast, individual differences in accuracy under conflict were selectively associated with greater activation in the right dorsolateral and right rostrolateral prefrontal cortices, independent of age. These findings suggest that right lateral prefrontal regions play an important role in successful interference control in early childhood, indicating that preschool Stroop-like control is not merely a weaker form of the adult left-lateralized system.