ABSTRACT
Message production begins with the formulation of a message and includes steps of discourse planning, lexical selection, and syntactic encoding prior to the final step of phonological production. Message comprehension begins with a text, presented aurally or visually, and ends with the recovery of a representation of that text as ideas or propositions. Errors, reflecting attentional lapses, processing limitations, and execution problems, can arise at any stage of production or comprehension. Normative aging processes, arising from general slowing of cognitive processes (Salthouse, 1992), reductions of working memory capacity (Light, 1991), or a breakdown of inhibitory processes (Hasher & Zacks, 1988), may exacerbate production or comprehension problems.
