Flexible selection of working memory representations to reduce cognitive cost

Across psychology, economics, and decision science, it is well established that choosing a good internal representation can make complex problems easier to solve ^1,2 . This idea, central to theories of bounded rationality ³ and heuristics ^4,5 , suggests that intelligent be-havior depends not only on what is stored in working memory, but on the format in which it is stored. Whether non-human animals flexibly select internal formats, and how such choices are implemented in neural circuits, has remained unclear. Here we show that rats adjust the format of working memory to reduce cognitive load. When a task encourages an action-based code, rats maintain the relevant information as a stable motor plan supported by frontal cortex. When the same task is reformulated to make this code costly, they in-stead store a sensory trace in auditory cortex. These strategy shifts are rapid and reliable, revealing that rats can switch between distinct neural circuits to store information in the most economical internal format. These results demonstrate that flexible representational selection is not unique to humans ⁶ but is present in rodents and reflected in circuit-level reallocation of working memory. This establishes a neural basis for classic theories linking problem representation to computational efficiency and provides a path toward a neural circuit-level description of selecting internal formats to reduce cognitive costs.