So far, Ernest has had environments with no own state, thus the right action for Ernest to choose did not depend on previous actions. But what if Ernest has to do a previous action in order to get a situation where he has the possibility to get a Y?
In this new environment, called "aA..bB..aA..aA", Ernest has to do two consecutive A or two consecutive B to get a Y. Further same consecutive actions will not lead to Y anymore. So, Ernest will only get a Y if he does A when he has previously done B then A, or if he does B when he has previously done A then B.
This trace shows Ernest 3.0 in this new environment. For better understanding, new labels have been used: "Learn new Schema" means Ernest memorizes a new schema (previously called "Mermorize schema"). "Recall Schema" means Ernest recalls a previously-learned schema that match the current context (previously called "Propose Schema" or "Avoid Schema"). Recalled schema having a X expectation have their weight displayed with the "-" sign (this was previously indicated by the "Avoid" term). This experiment begins with a "AA" initial environment's state. That causes Ernest to begin by learning a AXAX schema, which is OK.
Now, the environment does not always expects a specific action to return Y, there are some situations where any action from Ernest will lead to a X. Instead, the environment has a State made up of the two last Ernest's actions. Ernest will only get Y if he does A when the state is BA or if he does B when the state is AB.
As we can see, poor Ernest has to struggle hard to get Ys. He indefinitely gets one every once in a while, but he is unable to find a simple regularity aAbBaAbB that would give him a Y every second action.
Generally speaking, Enest is lost when the environment's regularities have a longer span than his context memory. I could easily make Ernest able to deal with this specific environment by increasing his context memory span, but I am looking for a more general solution. The basic idea is that Ernest should be able to construct "schemas of schemas".
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