Sparse Spatial Scaffolding for Visual Working Memory.

When holding information "in mind," it is vital to keep individual representations separated and selectively accessible for guiding behavior. Space is known to serve as a foundational scaffold for mnemonic individuation, yet the format and flexibility of spatial scaffolding for working memory remain elusive. We hypothesized that information in working memory can be recoded from its native format at encoding to organize and retain internal representations sparsely. To test this, we presented to-be-memorized visual items at distinct directions and distances and leveraged gaze biases during mnemonic selection as an implicit read-out of spatial scaffolding for working memory. We report how male and female humans abstract away over incidental item distance when direction alone suffices as a scaffold but incorporate distance when it aids mnemonic individuation. This suggests the flexible use of a sparse spatial scaffold for working memory, resorting to the minimal spatial scaffold required for the individuation of internal representations.