Age of acquisition, ageing, and verb production: normative and experimental data.

Young and old adults were shown pictured or written verbs and asked to name them as quickly as possible. Simultaneous multiple regression was used to investigate which of a set of potential variables predicted naming speed. Age of acquisition was found to be an important predictor of naming speed in both young and old adults, and for both word and picture naming. Word frequency predicted picture-naming speed only in older adults and failed to make any significant contribution to word-naming speeds for either group of participants. The respective loci and roles of age of acquisition and frequency in lexical processing are discussed in the light of these findings.