Most mind maps are shown as 2D views of a graph with central nodes. It is generally better for comprehension to see and interact with a 3D version of the same graph to understand the relations between its nodes.
In the paper Using augmented reality for visualizing complex graphs in three dimensions by D. Belcher, M. Billinghurst, S Hayes, and R. Stiles, published in the International Society for Mixed and Augmented Reality (ISMAR) 2003, the study results (link) showed that there is a significant advantage with reduced error for 3D views over 2D views of the same graph when trying to determine if nodes are connected (linked) to each other, which is a key capability when trying to comprehend a graph (or mind map).
The study shows that this improvement of 3D views and interaction with complex graphs also transfers to augmented reality, and not just desktop 3D. In the graph from the paper, you can see significantly reduced node link comprehension error for 3D desktop and AR over the conventional 2D case, and this relationship holds as the number of nodes in the scene scales up.
A study of the method of loci, entitled “Mnemonic Training Reshapes Brain Networks to Support Superior Memory” published in the March 2017 issue of Neuron by scientists at Stanford University, the Max Planck Institute of Psychiatry, and the Donders Institute shows the effectiveness of mnemonic training, specifically the method of loci, which results in significant recall improvement across time periods of twenty minutes, one day, and four months. Even after four months, the group using the method of loci had more than a 20% level of improvement in recall over the active and passive control groups.
The study included using functional magnetic resonance imaging (fMRI) of the subjects, testing their recall of words, and then comparing their before and after MRIs with memory athletes. They found the method of loci subject’s connections across brain centers came to resemble the memory athlete’s. In their study they show with a figure of the brain’s MRI connections the noticeable difference in connections between memory athletes and controls and indicate this improvement from using the method of loci may result from improved connections (links) across brain areas.
This study does not include AR or VR elements, but it does emphasize the use of the method of loci, where mental images of locations are used to recall items. In our Loci software, we functionally support placing objects in places for later recall consistent with the method of loci.