Attributes of ultrastability as an adaption mechanism in a hormone-modulated neural robot controller were investigated in a simulation. Action-selection based on hormone-driven utilities of memory items was used to alternate between resource gathering and recharging tasks.
The implemented ultrastability mechanism was applied on two different time scales, to regulate fast-operating neurons and slowly-operating glands. The main limitation of the algorithm was that the adaptation was unstable when a task required an unexpectedly varied satisfaction time.