The prioritized needs of the bug define the bug s behavior. Neural networks are a class of adaptive algorithms. Given a goal, like recognizing the meaning word, you can train the neural net to achieve the goal through contextual examples. The Norns in Creatures use neural nets to learn. Say, ball while your Norn is playing with a ball and the Norn eventually learns the word for ball.
Genetic algorithms are another class of adaptive algorithms.
A set of genes describes the methods each Creature uses to learn and solve problems. Often, with genetic algorithms, the world applies a fitness test and only the fit live to spawn another generation. In Creatures, the most visible fitness test is starvation. I had many unfit Norns starve to death. After hatching, baby Norns typically run outside to the garden where food is.