Canatil;in,|iiurn:il o| rx Itnr, \'a\ 61. No 1, JI Psvcholoijy t j>p\itj;lii 2')ir liy Ihc Can^idian l'syihnli>)jic:il Lexical Access in Younger and Older Adults; The Case of the Mass/Count Distinction . • • • Vanessa Taler, Institut Universitaire de Geriatrie de Montreal Biomedical Sciences Programme, Universite de Montreal Gonia Jarema, Institut Universitaire de Geriatrie de Montreal Biomedical Sciences Programme, Universite de Montreal Department of Linguistics, Universiie de Montreal Abstract Alihoiij^h lexictwtfmantic deficits are not rypically sft'ii in okk-r achills, some studies indicate that agc-rt'lalcci changes in semantic processing may occur. We had groups of older and ytuinger adults perform speeded lexical deci- sion on mass (e.g., honey), count (e.g., car), and dual nouns, which may be either mass or count (e.g., lamh). Singular dual nouns engendered significantly faster re.spon.se Uine.s in older aduiis than mass and count nouns, whereas younger adults manife.sted similar response times to count and dual nouns. These results point toward a three-way distinction in tlie lexicon between mass, count, and dual nouns. Older adults appear to treat a larger set of nouns as dual than do younger adults. This may be due to awareness of the mass/count ambiguity present in a greater number of lexical items, as a result of their greater linguistic experience. Alternatively, in order to conserve processing resources, older adults may not activate mass/count infor- mation when recognizing a dual noun unless a mass or count reading is forced by context. Meme si Ies dc'ficits lexicosemantiques ne sont par releves de U\<ion systematique chez Ies adultes plus ag^s. cenaines dtudes r^velent que des changements lies S I'age dans Ie traitement semantique peuvcnt se produire. Nous avoas clemandc' a des groupes cladultes plas jeunes et plus Hg^s d'effectuer des decisions lexicales acc<51^rees relativement i) la mas.se (p.ex. le miel), le denomhrement (p. ex. Ies voitures) et Ies noms doubles, qui peuvent con- cerner soit la masse ou le nombre (p, ex. agneau). Les noms doubles singuliers oni entraine des temps de reponse signincati\'enient plus courts chez les adultes plus ag^s que les noms de masse ou de d^nombrement, alors que les aduliL's plus jeunes manlfestaient des temps de reponse M-'inblabies pour les nom.s de denombrement et de masse. Ces r^sultats semblent demontrer une distinction a trois voies dans le lexitjue entre la masse, le denomhrement et ies noms doubles, l.es adultes plus ages semblent Iraiter un ensemble de noms comme double davantage que ne le font les adultes plus jeunes. Cela pourrait etre cause par une sensibilisation a lambiguite dans la masse/denombre- ment qui .se trouve dans un plus grand nombre de termes lexicaux, en consequence de leur plus grande experience linguistique. En revanche, afin d'^conomiser leurs res.sources de traitement. Ies adultes plus ages pounaient ne pas activer 1 information .^ur la masse/Uenombrement Iorsqu'ils reconnaisseni im nom double Jl moins qu'une lecture de masse ou de denombrement ne .soit foreee par le contexte. A considerable body of research on aging has revealed that various aspects of cogniiive function are subjecl to age-related decline. These decrements appear in a variety of tasks, including memory tasks that require self-initiated processing, such as cued and free recall (Park, 2000) and tasks tapping into episodic memory (Burke, MacKay, & James, 2000; Light, 1996; Wingfield & Stine-Morrow, 2000; for a review, see Craik, 2(X)0). Older adults also manifest deficits in cer- tain language tasks, such as word-finding difficulty (Burke, MacKay, Worthley, & Wade. 1991) and difficul- ty in retrieving proper names (Cohen & Faulkner, 1986; Maylor, 1990). There are, however, aspects of cognitive processing that appear to be well-preserved in healthy older adults. They are not typically thought to exhibit impair- ments on tasks that reflect the organization of lexicose- mantic knowledge, such as generation of word associa- tions (Howies, Williatns, & Poon, 1983; Burke c*t Peters, 1986; Lovelace & Cooley, 1982) and category exetii- plars (Howard, 1980). Likewise, oniine studies examin- ing lexicosemantic processing have shown similar respon.se patterns in older and younger aduUs. For example, frequency has been found to have similar eifects on lexical decision in the two ptipulations, although <.)verall reaction times (RTs) are somewhat slower in older adults (Allen, Madden, 8t Crozier 1991; Allen, Madden. Weber, & Groth, 199.S; Tainturier, Tremblay, & Lecours, 1989). Canadian journal of Experimental Psychology, 2007, 61-1, 21-34