<p>Experimental design and sample distribution.</p>

This study combines behavioral experiments with event-related potential (ERP) technology to explore the interactive effects of green advertising appeals and price premiums on consumers’ willingness to pay for green express packaging. Behavioral results reveal that price premium act as a primary structural barrier, with consumers’ green choices decreasing significantly as costs increase.

The ERPs data uncover the underlying psychological conflict during decision-making: in the early stage, high price premium elicited larger N2 amplitudes, reflecting increased cognitive conflict. Notably, egoistic appeals triggered the most pronounced N2 conflict under high-cost conditions. In the late evaluative stage, altruistic appeals significantly enhanced LPP amplitudes under low-premium conditions, reflecting higher motivational significance and moral satisfaction.