The representation of compound headedness in the mental lexicon: a picture naming study in aphasia.

Most compound words are constituted of a head constituent (e.g., light in moonlight) and a modifier constituent (e.g., moon in moonlight); the information transmitted by these head-modifier roles is fundamental for defining the grammatical and semantic properties of the compound and for identifying a correct combination of the constituents at the conceptual level. The objective of this study is to assess how lexical processing in aphasia is influenced by the head-modifier structure of nominal compounds. A picture-naming task of 35 compounds with head-initial (pescespada, swordfish, literally fishsword) and head-final (autostrada, highway, literally carroad) forms was administered to 45 Italian aphasic patients, and their accuracy in retrieving constituents was analysed with a mixed-effects logistic regression. The interaction between headedness and constituent position was significant: The modifier emerged as being more difficult to retrieve than the head, but only for head-final compounds. The results are consistent with previous data from priming experiments on healthy subjects and provide convincing evidence that compound headedness is represented at central processing levels.