A solution to Plato's problem: The latent semantic analysis theory of acquisition, induction, and representation of knowledge.

Abstract

How do people know as much as they do with as little information as they get?The problem takes many forms; learning vocabulary from text is an especially dramatic and convenient case for research.A new general theory of acquired similarity and knowledge representation, latent semantic analysis (LSA), is presented and used to successfully simulate such learning and several other psycholinguistic phenomena.By inducing global knowledge indirectly from local co-occurrence data in a large body of representative text, LSA acquired knowledge about the full vocabulary of English at a comparable rate to schoolchildren.LSA uses no prior linguistic or perceptual similarity knowledge; it is based solely on a general mathematical learning method that achieves powerful inductive effects by extracting the right number of dimensions (e.g., 300) to represent objects and contexts.Relations to other theories, phenomena, and problems are sketched.Prologue "How much do we know at any time?Much more, or so I believe, than we know we know!" -Agatha Christie, The Moving Finger A typical American seventh grader knows the meaning of 10-15 words today that she did not know yesterday.She must have acquired most of them as a result of reading because (a) the majority of English words are used only in print, (b) she already knew well almost all the words she would have encountered in speech, and (c) she learned less than one word by direct instruction.Studies of children reading grade-school text find that about one word in every 20 paragraphs goes from wrong to right on a vocabulary test.The typical seventh grader would have read less than 50 paragraphs since yesterday, from which she should have learned less than three new words.Apparently, she mastered the meanings of many words that she did not encounter.Evidence for all these assertions is given in detail later.This phenomenon offers an ideal case in which to study a problem that has plagued philosophy and science since Plato