The neuropsychological basis of trust propensity and trust dynamics in older adults with mild cognitive impairment: a multi-modal neuroimaging approach

Chen, Yiqi

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URN:	urn:nbn:de:bsz:180-madoc-716982
Document Type:	Doctoral dissertation
Year of publication:	2025
Place of publication:	Mannheim
University:	Universität Mannheim
Evaluator:	Alpers, Georg W.
Publication language:	English
Institution:	School of Social Sciences > Klinische u. Biologische Psychologie u. Psychotherapie (Alpers 2010-)
License:	Creative Commons Attribution 4.0 International (CC BY 4.0)
Subject:	150 Psychology
Keywords (English):	trust , mild cognitive impairment , computational modeling , functional MRI , structural MRI
Abstract:	Mild cognitive impairment (MCI), an early stage of Alzheimer’s disease, is associated not only with cognitive decline but also with social vulnerabilities, including heightened susceptibility to deception and withdrawal from relationships. Because trust is a cornerstone of social life, understanding how it changes in MCI is essential for both theory and practice. This dissertation investigates the psychological and neural mechanisms of trust in older adults with MCI within the neuropsychoeconomic framework of trust, which integrates affect, motivation, social cognition, and executive cognition. It addresses three central questions: (1) Trust propensity (TP): Does MCI alter initial willingness to trust strangers, and which large-scale resting-state networks account for such differences?; (2) Structural underpinnings: Do gray matter reductions in MCI explain lower TP, and if so, through which psychological components do they exert their influence?; and (3) Trust dynamics: How does MCI affect the ability to build, maintain, and withdraw trust during repeated social interactions, and what neural and computational mechanisms underlie these alterations? To answer these questions, three empirical studies were conducted. Experiment 1 combined a one-shot trust game with resting-state functional magnetic resonance imaging (fMRI) and connectome-based predictive modeling, showing that individuals with MCI exhibited reduced TP, explained by heightened betrayal sensitivity and increased reliance on the salience network. In contrast, healthy controls relied on social cognition and default-mode network connectivity. Experiment 2 used structural magnetic resonance imaging and voxel-based morphometry, revealing that atrophy in the anterior insula and thalamus mediated reduced trust in MCI through increased affective sensitivity to betrayal. Experiment 3 employed a multi-round trust game, computational reinforcement-learning modeling, and task-based fMRI. Results showed preserved trust-building with cooperative partners via compensatory activation in executive and social networks, but impaired trust reduction with non-cooperative partners, marked by slower updating, larger prediction errors, and disrupted executive–social connectivity. Together, these studies demonstrate that MCI reduces initial trust through affective hyper-sensitivity and undermines adaptive trust updating through social and executive dysfunction, while compensatory mechanisms support trust in supportive contexts. These findings advance the neuroscience of trust by extending an integrative model to a clinical population, identify neural markers of social vulnerability in MCI, and highlight trust as a potential target for early detection and intervention.