Partial Orders of Similarity Invariant between Brain and Perceptual Representations of Language

The idea of a hierarchical structure of language constituents of phonemes, syllables, words, and sentences is robust and widely accepted. Empirical similarities at every level of this hierarchy have been collected and analyzed in the form of confusion matrices for many years. By normalizing such data so that similarities are represented by conditional probabilities, simple orderings of similarities can be constructed. The intersection of two such orderings is an invariant partial ordering with respect to the two given orders. Such invariant partial orderings, especially between perceptual and brain orderings, but also between brain images of words generated by auditory or visual presentations, are the focus of this lecture. Data from four experiments are analyzed, with reasonable success in finding conceptually significant invariants.