Exploring tourists' pro-sustainable behavior in heritage tourism: an fsQCA approach based on self-determination theory – the case of Hue, Vietnam

Purpose This study examines how motivational regulation configurations lead to pro-sustainable behavior among heritage tourists, addressing gaps in understanding psychological mechanism beyond environmental behaviors alone. Design/methodology/approach Based on self-determination theory, this research employed fuzzy-set qualitative comparative analysis to analyze data from 639 tourists (382 domestic, 257 international) at UNESCO World Heritage sites in Hue, Vietnam. Five motivational regulations (external, introjected, identified, integrated, intrinsic) were examined as configurational conditions leading to pro-sustainable behavior across environmental, cultural, social and economic dimensions. Findings International and domestic tourists follow fundamentally different motivational pathways. International tourists achieve pro-sustainable behavior through one configuration combining introjected and identified regulation without external regulation, reflecting mid-levcel internalization. Domestic tourists follow five robust pathways with integrated regulation appearing in four configurations. External regulation operates contingently: undermining international tourists' mid-level autonomous motivation but productively supporting domestic tourists' identity-integrated motivation. Practical implications This study demonstrate that heritage managers should develop segment-specific strategies aligned with tourists' motivational pathways rather than universal approaches to encourage tourists’ pro-sustainable behavior in heritage context. Originality/value This study extends self-determination theory by demonstrating configurational rather than linear effects of motivational regulations in heritage contexts and reveal that cultural insiders require deep identity integration while cultural outsiders achieve sustainable behavior through mid-level internalization.