  Biological organisms must learn how to control their own bodies to achieve
deliberate locomotion, that is, predict their next body position based on their
current position and selected action. Such learning is goal-agnostic with
respect to maximizing (minimizing) an environmental reward (penalty) signal. A
cognitive map learner (CML) is a collection of three separate yet
collaboratively trained artificial neural networks which learn to construct
representations for the node states and edge actions of an arbitrary
bidirectional graph. In so doing, a CML learns how to traverse the graph nodes;
however, the CML does not learn when and why to move from one node state to
another. This work created CMLs with node states expressed as high dimensional
vectors suitable for hyperdimensional computing (HDC), a form of symbolic
machine learning (ML). In so doing, graph knowledge (CML) was segregated from
target node selection (HDC), allowing each ML approach to be trained
independently. The first approach used HDC to engineer an arbitrary number of
hierarchical CMLs, where each graph node state specified target node states for
the next lower level CMLs to traverse to. Second, an HDC-based
stimulus-response experience model was demonstrated per CML. Because
hypervectors may be in superposition with each other, multiple experience
models were added together and run in parallel without any retraining. Lastly,
a CML-HDC ML unit was modularized: trained with proxy symbols such that
arbitrary, application-specific stimulus symbols could be operated upon without
retraining either CML or HDC model. These methods provide a template for
engineering heterogenous ML systems.
