Adaptive gain control in the human dorsal anterior cingulate cortex

When making decisions, humans are often distracted by irrelevant information. Distraction has different impact on perceptual, cognitive and value-guided choices, giving rise to well-described behavioural phenomena such as the tilt illusion, conflict adaptation, or economic decoy effects. However, a single, unified model that can account for all these phenomena has yet to emerge. Here, we offer one such account, based on adaptive gain control, and additionally show that it successfully predicts a range of counterintuitive new behavioural phenomena on variants of a classic cognitive paradigm, the Eriksen flanker task. We further report that BOLD signals in the dorsal anterior cingulate cortex (dACC), rather than reflecting the cost of resolving conflict among responses, index a gain-modulated decision variable predicted by the model. This work unifies the study of distraction across perceptual, cognitive and economic domains, and offers new insights into the puzzling pattern of neural responses typically observed in the dACC.