I'm not actually convinced that negative examples are really necessary for learning empirical clusters in thingspace, especially if you're just trying to teach someone a subcategory of a big class they're already familiar with. If someone is already familiar with the concept of "bird" and you want to inform them that there is such a thing as blue jays, it may suffice to show them just a few instances of a blue jay (assuming you don't care whether they learn the terminology). Source: this super cool paper about one-shot learning using hierarchical Bayesian models: http://www.mit.edu/~rsalakhu/papers/MIT-CSAIL-TR-2010-052.pdf
In fact you are correct: Negative examples, as in examples outside the higher-order class, are not used in the teaching of sub-classes of a "higher-order noun". However, in discriminating between sub-classes, examples of other sub-classes serve as negatives for the sub-class you are currently teaching.
Please see chapter 11 in TOI, "Hierarchical Class Programs", p 123.
We do care that they learn the terminology. When I said they are not accessible through 'simple' verbal rules like: "Listen: a bird is a small feathered flapping wing...
I would like to request feedback on this comment, please.
I would also like to point out the cross-reference with jsalvatier's "What are good topics for literature review prizes?"