When expectancy meets emotional and effort costs: A longitudinal situated expectancy-value theory study regarding conditional indirect effects on mathematics achievement via maladaptive motivational engagement.

Situated expectancy-value theory emphasizes contextual influences on motivation, yet perceived cost remains underexplored relative to expectancy-value interactions.In Taiwan's high-pressure academic context, we examined whether the relationship between expectancy and mathematics achievement is mediated by maladaptive motivational engagement (MME), and whether this indirect pathway is conditional on students' emotional and effort costs.Using three-wave data from 733 seventh-grade students over 18 months, mediation and moderated mediation analyses were conducted through structural equation modeling.Results supported a partial mediation effect: students with higher expectancy beliefs were less likely to engage in MME, which in turn was associated with better achievement.However, this indirect pathway was moderated by students' perceived costs.Specifically, emotional cost attenuated the indirect pathway: The indirect effect was present only at low levels of emotional cost and diminished to nonsignificance as emotional cost increased.In contrast, effort cost exhibited a nonlinear reversal pattern: The indirect effect was statistically significant at low levels, became statistically nonsignificant at moderate levels, and reversed only at the extreme high end-suggesting that expectancy was linked to more MME and lower achievement when students perceived mathematics as extremely effortful.These findings underscore that although higher expectancy beliefs generally buffer against MME and facilitate achievement over time, their benefits may be undermined or even reversed under high-cost conditions.By clarifying how emotional and effort costs moderate this pathway in distinct ways, this study advances situated expectancy-value theory and highlights the need to address nuanced perceptions of cost in highpressure academic contexts. Educational Impact and Implications StatementThis study shows that students' beliefs in their ability to succeed can support long-term academic achievement by reducing disengaged or maladaptive motivational behaviors.However, this positive pathway weakens-or even reverses-when students feel emotionally overwhelmed or perceive academic tasks as overly effortful.These findings suggest that promoting student motivation requires more than boosting confidence; it also demands attention to the emotional and effort-related burdens students experience, particularly in high-pressure educational environments like Taiwan.Addressing both students' confidence and their perceived burdens is essential to sustaining engagement and achievement across time.