In the context of the digital era, social media have profoundly changed tourists' information acquisition and decision-making process. This study constructed a comprehensive theoretical framework integrating the Theory of Planned Behavior (TPB) and the Involvement-Attachment Model (IAM) to explore the dual moderating effects of social media inclination and media exposure on the mechanism of tourists' tourism intention formation. The study utilized a cross-sectional survey design and collected data through social media platforms, obtaining 385 valid questionnaires (valid recovery rate 89.95%). Partial least squares structural equation modeling (PLS-SEM) was used to analyze the data.

The results of the study showed that (1) all three core constructs of TPB (attitude, subjective norms, and perceived behavioral control) significantly and positively affected tourism intention, with the strongest effect of attitude (β=0.312, p<0.001); (2) tourism engagement strongly and positively affected place attachment (β=0.724, p<0.001), and place attachment in turn significantly affected tourism intention (β= 0.267, p<0.001); (3) tourism engagement, as a pivotal variable, significantly influenced the three core TPB constructs (β values of 0.615-0.660), connecting affective engagement with cognitive appraisal; and (4) social media tendency significantly positively moderated engagement's effect on attitude (β=0.124, p<0.01) and subjective norms (β=0.156, p<0.001) (β=0.156, p<0.001) and mainly on the cognitive path; and (5) media exposure significantly positively moderated the effect of place attachment on tourism intention (β=0.142, p<0.01) as well as the effect of involvement on place attachment (β=0.118, p<0.01), mainly on the affective path. The integrated model explained 68.7% of the variance in travel intentions, which was significantly higher than the traditional single theory model.

The theoretical contributions of this study are: the first systematic integration of the TPB and IAM frameworks to construct an integrated model covering the dual mechanisms of cognitive decision-making and emotional attachment; the pivotal role of tourism engagement revealed; and the differential moderating mechanisms of social media inclination and media exposure identified. Practically, the study provides guidance on multidimensional marketing strategies for destination managers and tourism enterprises, emphasizing that attention should be paid to both tourists' cognitive appraisal and affective attachment, and differentiated strategies should be implemented for user groups with different social media usage characteristics.