Not @Jojker, but here is my take:
That exploration and evaluation is a mechanism, just a higher-order one. Nothing happens without a mechanism.
And once all maps are populated, by the end of adolescence at the latest, the brain stops learning?
There always is a displacement of lower-predictive-value old memories. “Drive”, “want”: these anthropomorphic terms are misleading when we are talking about simple low-level mechanisms.
All that neurons are doing is recognising patterns: coincident inputs. Strong patterns propagate upstream and laterally (perhaps in @Bitking’s hexagons), while also suppressing downstream: predictable / low-additive-value future inputs. Weak / suppressed nodes invite replacement inputs from neighbouring downstream areas. I think your basic “pertinence” is downstream reinforcement of novelty vs. predictability, overlayed on upstream-detected input pattern strength. With similar lateral mechanisms of inhibition among same-source (expected coincidence) co-activated nodes, and reverberation among different-source (unexpected coincidence) co-activated nodes.