This study is situated within the theoretical framework of political psychology and examines how presidential personality traits shape South Korea’s North Korea policy. While mainstream international relations scholarship has long emphasized structu...
This study is situated within the theoretical framework of political psychology and examines how presidential personality traits shape South Korea’s North Korea policy. While mainstream international relations scholarship has long emphasized structural and institutional constraints, the oscillation of South Korean presidents’ approaches toward Pyongyang under otherwise stable systemic and domestic conditions suggests that structural explanations alone are insufficient. For instance, Kim Dae-jung advanced the “Sunshine Policy,” Lee Myung-bak and Park Geun-hye adopted more confrontational stances, Moon Jae-in returned to dialogue and engagement, and Yoon Suk-yeol shifted back toward deterrence and coercion. Such cyclical variation underscores the explanatory value of leaders’ personalities and decision-making styles as key micro-level variables. Accordingly, this study aims to contribute to the political psychology of South Korea by offering a case analysis that highlights the interaction between presidential personality and foreign policy, while providing insights into the possible trajectories of Seoul’s future policy toward the North.
Theoretically, the dissertation develops a mechanism model—“context → traits → channels → policy outputs”—that integrates Leadership Trait Analysis (LTA) and Operational Code Analysis (OCA) within a neoclassical realist and political psychology framework. This model systematizes the causal linkage between leaders’ psychological traits and foreign policy by demonstrating how individual-level variables are filtered through three mediating channels—responses to constraints, openness to information, and motivational orientation—before being translated into dimensions of policy intensity, agenda sequencing, and genre of policy expression. In doing so, it illuminates why, under broadly similar institutional and external environments, differences in presidential personality yield divergent policy pathways.
Methodologically, the study employs a “most similar systems, different leaders” design. It systematically collected Moon Jae-in’s (2017–2022) and Yoon Suk-yeol’s (2022–2025) public speeches, policy addresses to the National Assembly, statements in multilateral settings, and social media texts, resulting in 20 and 15 representative corpora respectively, with total word counts of 91,015 and 90,142. Adhering to LTA’s textual criteria, the study used Profiler Plus (v7.3.15) to code seven core traits and produce quantifiable indicators of personality. Supplementary validation was conducted through OCA, and process-tracing and temporal juxtaposition were used to align trait scores with key policy events—including the Berlin Initiative, the Panmunjom and Pyongyang Declarations, Yoon’s “Audacious Initiative,” and the resumption of U.S.–ROK joint military exercises—thereby enhancing the causal observability of the findings.
The analysis reveals systematic differences in the presidents’ cognitive structures and leadership styles. Moon Jae-in, consistent with Hermann’s typology, approximates a charismatic style, characterized by high power motivation, strong in-group bias, high cognitive complexity, low self-confidence, low distrust, and low task orientation. This profile inclined him toward agenda leadership tempered by team reliance, openness to diverse perspectives, and relationship-oriented strategies that advanced gradual cooperation. His policy practice emphasized dialogue, multilateral mechanisms, and humanitarian exchange. By contrast, Yoon Suk-yeol more closely resembles an expansionist leader, displaying high power motivation, low in-group bias, low cognitive complexity, low self-confidence, moderate distrust, and high belief in his ability to control events. His direct and forceful style privileged institutionalized tools and alliance mechanisms to signal deterrence, favoring rapid, concentrated, and high-intensity responses to security challenges.
Leadership style further conditioned their policy orientations. Moon’s higher cognitive complexity enabled multidimensional information integration, reliance on core advisors, cautious risk perception, and inclusive multilateral communication. Yoon, with lower cognitive complexity, relied more on institutionalized procedures than fixed advisory circles, magnified security threats in risk perception, and adopted a clearer, rule-bound, deterrence-focused communication style. Consequently, Moon’s policy decisions followed gradual, low-intensity pathways with agendas centered on cooperation, humanitarian, and economic issues, whereas Yoon prioritized security, deterrence, and alliance commitments, adopting rapid, high-intensity instruments. In crisis settings, Moon tended to avoid escalation and keep dialogue channels open, while Yoon quickly signaled firmness, set conditional thresholds, and emphasized securitization and bloc-oriented rhetoric in international forums.
Taken together, the findings suggest that cognitive structures influence leadership styles, which in turn shape policy decision forms, generating distinct causal pathways. Moon’s high cognitive complexity and relational orientation drove him to advance policy within institutional and multilateral frameworks, gradually building trust and cooperation. Yoon’s strong belief in control and high power motivation heightened his sensitivity to threats and his preference for direct responses through institutionalized alliances and deterrent measures. The comparison demonstrates that presidential traits not only determine leadership styles but also, through these mediating channels, shape concrete policy intensity, sequencing, and expression—constituting an essential psychological mechanism for explaining policy divergence under comparable structural conditions.
This dissertation makes three contributions. First, it advances the localization of political psychology in Korean international relations by developing and testing a mechanism model that links leader traits to policy dimensions through mediating channels. Second, it provides empirical evidence of how presidential personality differences generate divergent North Korea policies, enriching the theoretical role of individual-level variables in neoclassical realism. Third, it establishes a replicable methodological paradigm—multi-source corpus collection, localized dictionary adaptation, machine coding, norm-referenced comparison, and temporal validation—that future research can adopt.
By integrating cross-period, multi-contextual textual data with quantitative psychological tools, this study offers a systematic analysis of South Korean presidential personality and North Korea policy. Methodologically, it combines remote textual measurement with content analysis, advancing the observability of personality variables in East Asian foreign policy research. The findings suggest that leadership traits serve as indispensable indicators for understanding and explaining presidential foreign policy orientations.