The 'made-up mind'. Deriving new hypotheses on delusions from general psychological models of belief maintenance

Contemporary definitions of delusions highlight their resistance to conflicting evidence as the core feature, but there has been little progress in understanding why even explicit confrontation with contradicting evidence seldom leads to belief revision. This review aims to generate new hypotheses on delusion maintenance to inform research and clinical practice. We systematically reviewed psychological models of belief maintenance and extracted their proposed mechanisms and moderators. The electronic search identified six dissociable perspectives: Associative learning, Bayesian inference, utility-informed, cognitive processing informed, dissonance-theory informed, and cross-disciplinary perspectives. The proposed mechanisms involved changing the sensory evidence to fit with one's prior belief (e.g. shifting attention to contextual cues, changing or reinterpreting sensory input), reducing the relevance of the prediction error (e.g., finding causes of the unexpected event, increasing the abstraction of the prior belief) and reinforcement (e.g. reduction of arousal). The moderators related to prior belief (e.g. its temporal stability, utility, or self-relevance), size of the prediction error, precision of the sensory evidence (e.g. quality, order), context (e.g. typicality, complexity), and individual differences (e.g. cognitive flexibility). We discuss how each proposed mechanism and moderator and their interactions align with current knowledge on delusions and offer compelling and novel explanations for delusion maintenance. We conclude that delusion maintenance and systematization can be convincingly explained by combinations of prior belief precision, ambiguous input and situational characteristics and may not necessarily require neurobiological deficits or generalized biases. The hypotheses derived offer multiple new avenues for research and for optimizing the learning process in interventions for delusions.