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

Abstract

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.

• Compound words
• Picture naming
• Compound headedness
• Aphasia.

Preliminary results of this study were presented at the 48th Annual Meeting of the Academy of Aphasia (Athens, 2010) and the 29th European Workshop on Cognitive Neuropsychology (Bressanone, 2011).

The study was supported by a grant awarded to C. L. by the University of Milano-Bicocca (Fondo d'Ateneo per la Ricerca (FAR) 2009).

Notes

¹ It may be argued that constituent accuracy could also be tested as a predictor in a regression analysis on compound naming accuracy, to assess to what extent the probability of retrieving the constituents affects the probability of retrieving the whole word. This effect could be modulated by constituent position and/or compound headedness, thus providing information on the representation of head-modifier roles in the mental lexicon. This analysis was run in the present study, but the interactions of interest between constituent accuracies, constituent position, and headedness were not significant—that is, constituent accuracy was helpful for compound retrieval irrespective of position and head-modifier roles.

² With regard to the effects of the covariates on the probability of specific error types, the only association found was between aphasia severity and constituent omissions: Constituents were omitted more frequently by patients suffering from more severe impairments (p = .0246).

³ The prescriptive and the distributional interpretation of the right-hand head rule (Williams, 1981) are not necessarily at odds. Di Sciullo and Williams (1987) proposed that only head-final compounds would be real morphological constructs, whereas head-initial compounds are syntactic strings imported into the lexicon. Head-final compounds may thus be more numerous because they are generated through a standard morphological operation.