From Exemplar Theory to Population Coding and Back. An Ideal Observer Approach

Exploiting the analogy between exemplar models and population coding schemes, we characterize, by means of information theoretic tools, the efficiency of a large but finite population of cells coding for a discrete set of categories (e.g. vowels). The optimal code is shown to typically allocate more cells to class boundaries than to regions further apart. We then discuss the predicted perceptual consequences and review existing exemplar models in the light of our general results.