The elusive happy personality: affective and cognitive mechanisms underlying personality and well-being functioning

<p dir="ltr">The study of personality and well-being is a key area of research, as both significantly impact behaviour and life outcomes. This thesis addresses critical gaps in personality psychology by proposing integrative frameworks for understanding personality and well-being functioning. Despite progress in personality research, the field is hindered by fragmentation, circular reasoning, and a lack of multilevel explanatory theories. Existing models, such as the Big Five, offer descriptive insights but fail to elucidate the mechanisms underlying trait expression and their impact on well-being. To address these challenges, the thesis develops a rigorous and systematic approach to theory construction that promotes integrative science and a formal explanatory model of personality and well-being functioning.</p><p dir="ltr">In response to the challenges posed by the fragmented nature of existing personality theories, this thesis introduces the Systems Theory and Abductive Reasoning (STAR) framework, which provides a systematic approach to theory construction to advance the integrative science of personality and well-being. In conjunction, this thesis proposes the Situation-Perception-Affect-Cognitive control-Expressed behaviour (SPACE) model, which offers a unified model of the processes underlying personality and well-being functioning.</p><p dir="ltr">Grounded in the STAR framework, the SPACE model conceptualises personality as a system of perceptive, affective, and cognitive fundamental units with their parameters of temporal dynamics. A key feature of the SPACE model is its emphasis on the primacy of individual differences in affective dynamics, in interaction with situational features, executive functions, and basic values, in predicting behaviour as well as personality and well-being functioning. This formal model is designed to be both theoretically robust and empirically testable.</p><p dir="ltr">By providing criteria for theory construction, STAR facilitates the integration of personality research with adjacent disciplines, fostering interdisciplinary coherence. The SPACE model advances the development of a cumulative science of personality by providing a significant step towards a coherent general explanation of personality and well-being functioning and individual differences. By incorporating domain-specific processes and temporal dynamics, the model offers a comprehensive explanation of personality functioning. It addresses key challenges, such as trait stability, the role of values in behaviour regulation, and the pathways to intentional trait change. This research highlights gaps in research and provides insights for improving well-being through targeted interventions, bridging gaps between theory and application.</p>