Background
Japanese cultural psychology often anticipates a "middle way," implying optimal outcomes when Stress-is-Enhancing (SEM) and Stress-is-Debilitating (SDM) beliefs are balanced. We contrasted this dialectical view with a graded resource account in which outcomes chiefly improve as SEM increases.
Methods
Three cohorts of Japanese university students (N=1,406) completed the SMM-J and measures of stress exposure, appraisal (PSS total, distress, "eustress"), coping (problem-, emotion-, avoidance-focused), and well-being (positivity, positive affect, mental health). CFA (WLSMV) tested factor structure and multigroup invariance. Outcomes were modeled as quadratic functions of cohort-centered SEM and SDM using response surface analysis (RSA), estimating a1-a4 and ΔR²; cross-cohort shape equivalence was assessed.


Results
CFA supported a correlated two-factor structure with strong invariance; SEM and SDM were inversely related. Bivariate patterns replicated prior work. RSA indicated chiefly linear gradients: higher SEM predicted better adaptation (positive a1 and/or a3), and a concave "middle-is-best" along the LOC (a2<0) did not emerge. LOI curvature (a4) was modest and outcome-dependent: mismatch related to higher perceived distress, whereas some adaptive indices (e.g., positive affect, coping mobilization) increased with mismatch. ΔR² effects were small yet non-trivial.


Discussion and Conclusion
The linear SEM advantage accords with evidence that mindsets bias appraisal toward challenge and energize approach-oriented coping, whereas SDM aligns with avoidance and distress. Weak LOC/LOI curvature likely reflects attenuation of higher-order effects by measurement error, mid-range and partly controllable academic stressors that yield quasi-linear functions, and East-Asian dialecticism that tolerates contradiction without privileging a fixed "middle." Outcome-specific a4 echoes response-surface findings on affect mixtures: ambivalence can elevate distress yet coincide with greater activation or coping mobilization. Overall, results support a graded resource account; SEM appears to operate as an upstream regulator of appraisal and coping across domains.