We also found that neural dimensionality is related to the concreteness of each subject’s recollection. Subjects who focus on concrete details, as opposed to abstract aspects of the movies, tend to share more dimensions with others.

These neural differences matter! Fine-grained structure in higher dimensions of cortical activity predicts behavioral differences during recall—even after accounting for coarse-scale effects captured by standard methods.

In our new work, we find that the ways individual brains differ are *not* constrained to a few dominant patterns. We find distinct patterns in how individual brains process natural movies along many latent dimensions, and these differences are reliable across different movies.