On the computational basis of learning and cognition: Arguments from LSA ------------------------------------------------------------------------ by Landauer Here are some notes and questions I wrote down while reading the paper. Its main point is to argue that learning from empirical association, if done right and writ very large, is capable of much more than often supposed. "coincidence, co-occurrence, contingency, or correlation" vs. experiment? contiguity vs. similarity (Locke's view). How do we compute similarity? "It is intimately related to object identification and recognition, whether innate or learned, and to generalization, categorization, induction, prediction, and inference.": Can we make this concrete? The paper argues that LSA has achieved success with verbal semantics and the same should hold for vision. How can we test this? Is "words vs. words" data really different from "words vs. contexts"? Does anyone know about "geons"? If we want to use dimension reduction approaches in vision, we'll need something like this. pg. 16: Sure, memory of a passage isn't word for word, but we'll remember *some* of the words and phrases. Clearly, there are multiple components to representation. Does LSA's representation qualify as a representation? Do we have guidelines on what's needed to be a representation? What should a representation be able to do? How can we evaluate it? pg. 17: By the way, they didn't really test 66,000 dimensions. pg. 23, "Surprisingly, the field of information retrieval research has never developed a technology for comparing the accuracy of machine and human performance in this task, so we do not know whether the LSA enhancement meets this objective.": Really? Scoring similarity is obviously a very important job of a representation. But, it is not sufficient for all tasks. What do we require of our representation to allow it to be used for natural language generation? pg. 35, Chomsky: "barring miracles ... Children must be basically acquiring labels for concepts they already have." Them's fighting words! pg. 40: "The worst offender, in my opinion, is explanation by positing rules." pg. 47, "In Edelman's terms, the claim is that representation is representation of similarity, rather than representation of structures or properties. ... It yields what animals and humans need, recognition, identification, generalization, categorization, by computations on the available evidence: empirical association in space and time." CLASS NOTES by Eiman Elnahrawy (edited by me) =========== When we switched from document representation to vision we changed the dimensions of the representation matrix from (words X passages) to (objects X images). Then, professor Hirsh suggested a 3X3 pixels to correspond to words rather than the use of objects. He mentioned that a similar approach is used in foreign languages (other than English) where 3 characters are used instead of words. I recall one comment that these 3 characters may indeed identify some specific words. An example was the 3 characters UFA and the word manUFActure. Then, we discussed an outline for representation. The topics were as follows. - Span levels - Similarities - Registration/ Unification, matching (This is how to align two - objects. Similarities are then based on the alignment.) - Task Specifity - Abstraction - Generalization Via Hierarchy? (There was a debate about this). - Compositionality