Decoding Belief Dynamics in the Brain: An ALE Meta-Analysis of Neural Correlates in Belief Formation and Updating

Introduction: Understanding how individuals form and update their beliefs is a fundamental aspect of human cognition. Belief formation refers to the initial development of an individual's belief, while belief updating describes the process by which individuals revise their existing beliefs. Although these two processes are often interwoven, they might operate through different neural mechanisms. Moreover, we suggest that a further dissociation could concern the way belief formation has been usually investigated. Approaches based on Theory of Mind are often opposed to other approaches, emphasising the role of individual or situational factors in belief formation. Notably, we propose that this differentiation might reflect the engagement of social and non-social dynamics within belief formation. Methods: Using activation likelihood estimation (ALE; Eickhoff et al., 2009) we conducted a meta-analytic review of 28 fMRI studies (484 activation foci) selected through the PRISMA guidelines with the specific aims: 1) to identify and disambiguate neural correlates specifically underlying belief formation and belief updating and 2) to test the possibility of a dissociation between neural correlates underlying belief formation under social and non-social environments. The Fail-Safe N (FSN) method was used to evaluate the validity of our results and check for the weight of publication bias. Results: The general ALE meta-analysis revealed activation clusters in both hemispheres, primarily in the Precuneus (PCun) and Temporo-Parietal Junction (TPJ), as well as in the left Supplementary Motor Area (SMA) and anterior Insula (aIns). For Belief Formation, five clusters were identified, but only bilateral TPJ was robust to FSN control. Belief Updating revealed a single robust activation in the left PCun. Conjunction analysis showed shared neural networks between the two processes, particularly in the left PCun, while contrasts highlighted distinct regions: TPJ for Belief Formation and medial prefrontal cortex for Belief Updating. Social and Non-Social Belief Formation involved distinct neural correlates, with TPJ for social and the middle occipital gyrus (MOG) for non-social beliefs. Discussion: Activation of the right PCun during belief updating suggests its role in perspective-taking, enabling shifts in viewpoint necessary to adapt beliefs (Cavanna & Trimble, 2006). The TPJ bilaterally engaged in belief formation, indicate their function as a neural "template", assessing environmental information for congruence or discrepancy with existing beliefs (Doricchi et al., 2022). Activation in medial prefrontal regions (SMA/ACC), highlights their role in solving conflicts between competing beliefs and in the strategic planning required for belief integration. Finally, the MOG involved in non-social belief formation, points to its contribution in modifying beliefs through visual representation and perspective construction, facilitating the mental simulation of alternative realities.