Event-related potentials to rare visual targets and negative symptom severity in a transdiagnostic psychiatric sample

•P3b and N2b mean amplitudes were inversely related to the Positive and Negative Syndrome Scale – Negative Symptom Factor severity score across a transdiagnostic psychiatric sample.•A significant negative transdiagnostic relationship was found between P3b mean amplitude and blunted affect severity.•This suggests that people with a greater severity of blunted affect may not allocate sufficient cognitive resources engaging in activities requiring selective attention.