Purpose: Of the three currently recognized variants of primary progressive aphasia, behavioral differentiation between the nonfluent/agrammatic (nfvPPA) and logopenic (lvPPA) variants is particularly difficult. The challenge includes uncertainty regarding diagnosis of apraxia of speech, which is subsumed within criteria for variant classification.…

A theory for representation of concepts in memory is proposed which emphasizes the association of salient exemplars with the concept. Previous theories dealing with the classification processes involved in acquiring new concepts have shown that clear category boundaries do not exist. It is proposed that present theory must account for the…

Meyer found subjects were faster to determine if a stimulus word was a member of either of two prespecified categories if the categories were close in meaning. A reanalysis of the data favors instead a model emphasizing the role of decision-making processes in categorization and flexibility of task strategies. (CHK)

Analyzes attributes of symbols and identifies the need for a suitable management system for retrieving images from a database. A classification structure that incorporates graphic, semantic, and bibliographic dimensions is described; experiments with describing, sorting, and drawing symbols are reviewed; and future work on a database management…