Synonym / Terms for "learned" and "not learned"

Solution 1:

In the context of psycholinguistic experiments, you sometimes see:

• Condition A is trained
• Condition B is naïve

Another user has suggested control and experimental, but for me, this implies that the untrained group will be regarded in statistical analysis as a baseline of no experimental interest. But this might not be the case for various reasons: for example, one may be interested in interference or learning effects which unfold throughout the presentation of stimuli.

By the way, not sure if you are German ("muss nicht..."), but "must not have taken place" should be "need not have taken place" in English ;-)