The study investigates the structural and polarization changes in bismuth sodium titanate (BNT)-based ceramics, specifically 0.2(Ba₀.₈Sr₀.₂TiO₃)−0.8(Bi₀.₃Na₀.₅TiO₃), to challenge the classical view that polarization is primarily due to the off-center displacement of B-site cations. Using high-resolution powder neutron diffraction, impedance spectroscopy, and ab initio calculations, the researchers find that Ti⁴⁺ contributes less than a third to the overall polarization, while significant contributions come from O²⁻ ions and A-site cations, particularly Bi³⁺. The detailed examination of the ferroelectric transition reveals unexpected local structure evolution, challenging traditional understandings of polarization behavior in perovskite-structured systems. The findings offer insights into the understanding of such transitions in other ferroelectric perovskites, especially those containing lone pair elements.The study investigates the structural and polarization changes in bismuth sodium titanate (BNT)-based ceramics, specifically 0.2(Ba₀.₈Sr₀.₂TiO₃)−0.8(Bi₀.₃Na₀.₅TiO₃), to challenge the classical view that polarization is primarily due to the off-center displacement of B-site cations. Using high-resolution powder neutron diffraction, impedance spectroscopy, and ab initio calculations, the researchers find that Ti⁴⁺ contributes less than a third to the overall polarization, while significant contributions come from O²⁻ ions and A-site cations, particularly Bi³⁺. The detailed examination of the ferroelectric transition reveals unexpected local structure evolution, challenging traditional understandings of polarization behavior in perovskite-structured systems. The findings offer insights into the understanding of such transitions in other ferroelectric perovskites, especially those containing lone pair elements.