Inferences on a multidimensional social hierarchy use a grid-like code

Cognitive maps are theorized to enable generalizing experiences in new situations. Park et al. show that non-spatial experiences sampled piecemeal are integrated into a two-dimensional cognitive map of social hierarchy, and a grid code is used for novel inferences. Generalizing experiences to guide decision-making in novel situations is a hallmark of flexible behavior. Cognitive maps of an environment or task can theoretically afford such flexibility, but direct evidence has proven elusive. In this study, we found that discretely sampled abstract relationships between entities in an unseen two-dimensional social hierarchy are reconstructed into a unitary two-dimensional cognitive map in the hippocampus and entorhinal cortex. We further show that humans use a grid-like code in entorhinal cortex and medial prefrontal cortex for inferred direct trajectories between entities in the reconstructed abstract space during discrete decisions. These grid-like representations in the entorhinal cortex are associated with decision value computations in the medial prefrontal cortex and temporoparietal junction. Collectively, these findings show that grid-like representations are used by the human brain to infer novel solutions, even in abstract and discrete problems, and suggest a general mechanism underpinning flexible decision-making and generalization.

Automated summary

The study found that the human brain uses grid-like representations to infer direct trajectories between entities in a reconstructed abstract space during discrete decisions. These results suggest that grid-like representations are used for inferring novel solutions, even in abstract and discrete problems, indicating a general mechanism supporting flexible decision-making and generalization.