The relationship between individual differences in gray matter volume and religiosity and mystical experiences: A preregistered voxel-based morphometry study.

Religiosity and mystical experiences show no structural brain differences in gray matter volume. In a confirmatory voxel-based morphometry analysis of 211 participants, region-of-interest testing found no evidence that religiosity is associated with reduced volume of the orbito-frontal cortex or changes in the bilateral inferior parietal lobes. Mystical experiences were not linked to reduced volume of the hippocampus, right middle temporal gyrus, or inferior parietal lobes. Whole-brain analysis also found no structural brain differences related to religiosity or mystical experiences. The authors suggest research should shift from studying structural brain differences to functional and multivariate approaches.

Study at a glance

Abstract

The neural substrates of religious belief and experience are an intriguing though contentious topic. Here, we had the unique opportunity to establish the relation between validated measures of religiosity and gray matter volume in a large sample of participants (N = 211). In this registered report, we conducted a confirmatory voxel-based morphometry analysis to test three central hypotheses regarding the relationship between religiosity and mystical experiences and gray matter volume. The preregisterered hypotheses, analysis plan, preprocessing and analysis code and statistical brain maps are all available from online repositories. By using a region-of-interest analysis, we found no evidence that religiosity is associated with a reduced volume of the orbito-frontal cortex and changes in the structure of the bilateral inferior parietal lobes. Neither did we find support for the notion that mystical experiences are associated with a reduced volume of the hippocampus, the right middle temporal gyrus or with the inferior parietal lobes. A whole-brain analysis furthermore indicated that no structural brain differences were found in association with religiosity and mystical experiences. We believe that the search for the neural correlates of religious beliefs and experiences should therefore shift focus from studying structural brain differences to a functional and multivariate approach.