Planning in Nonhuman Primates Emerges from Structure Knowledge and is Distinct from Attention, Working Memory, Effort Control, and Learning

Forward planning involves mentally simulating future choices. Such mental simulation may constitute an independent cognitive operation, or it may be intricately linked to canonical cognitive operations supporting working memory of choice options, covert attentional information sampling, forming memory models of problem structure and effort control for pursuing future goals. Here, we test the relative independence of planning in non-human primates with an object-sequence planning task assessed together with an assay of simpler cognitive tasks. The sequence task unexpectedly masked objects at future serial positions probing NHPs to plan ahead serial future choices. We found that five of six subjects planned ahead 2-3 ordinal positions. Planning depth was predicted by knowledge of the serial structure but constituted a unique cognitive factor that was distinct from sequence memory, object memory, and learning efficacy. Similarly, planning was segregated from working memory capacity, attention, inhibitory control and effort control. These findings suggest that planning ahead constitutes a separate construct not reducible to other domain-general cognitive operations, and emerges in NHPs that successfully form an internal model of the problem structure.