br Conclusions br Conflict of interest br Acknowledgements T
Conflict of interest
Acknowledgements This work was supported by National Institutes of Health (R01MH070890-09A1 to JHG); Foundation of Hope for Research and Treatment of Mental Illness Award to WG and UNC-Chapel Hill start-up to WG. We are extremely grateful to the many research assistants (in chronological order) who conducted the Mullen and working memory assessments for this paper: Hillary Langley, Sarah Palmer, Portia Henderson, Molly McGinnis, Emily Bostwick, Sadie Hasbrouck, and Monica Ferenz. The authors declare no competing financial interests.
Introduction While language production in adult speakers has been studied extensively, relatively little is known about the processes involved in children\'s production of words and sentences. Models of the adult speaker posit a sequence of steps during production, from conceptual encoding via lemma selection, morphological and phonological encoding, and finally motor execution and articulation (e.g., Indefrey and Levelt, 2004). The temporal sequencing of these processes has been studied in detail using behavioural and neurophysiological measures leading to the proposal that morphological encoding occurs at about 250–330ms after the stimulus, which is later than semantic encoding (175–250ms) but earlier than phonological (330–455ms) encoding (see e.g., Strijkers and Costa, 2011; Janssen et al., 2011). Neurophysiological studies of the time-course underlying language production processes in children are particularly rare (Budd et al., 2013), and the question of whether the temporal sequencing of language production processes posited for adults also holds for children remains largely unanswered. A number of previous brain-imaging studies have reported developmental changes of the Epinephrine Bitartrate networks involved in language production. For instance, it has been proposed that focused left-lateralized networks controlling, for example, silent naming, have emerged from bilateral networks during late childhood and adolescence (e.g., Lidzba et al., 2011; Everts et al., 2009), leading to speculations about how these changes in brain development can impact on language (and other higher cognitive) processes. Against this background, the question of whether adults and children make use of comparable mechanisms for language production becomes even more relevant. The present study contributes new findings to this under-researched issue by investigating processes involved in children\'s (in comparison to adults’) production of morphologically complex words using ERPs. The specific phenomenon we studied is the distribution of singular and plural modifiers inside compounds. In English, for example, compounds with singular modifiers are more acceptable than those with plural ones, and amongst those with plural modifiers, compounds with regular plural modifiers are less acceptable than those with irregular ones; compare goose/duck feeder,?geese feeder, *ducks feeder (e.g., Haskell et al., 2003; Cunnings and Clahsen, 2007). The so-called plurals-in-compounds effect is subject to a number of subtle linguistic constraints (see below), which have been widely studied in the psycholinguistic literature, albeit mainly in behavioural experiments. Plurals-in-compounds have also played a prominent role in debates concerning the nature of children\'s language development and in the controversy between symbolic rule-based versus associative models of language (e.g., Pinker, 1999). Three-year-old children already demonstrated adult-like knowledge of this phenomenon (e.g., Gordon, 1985; Alegre and Gordon, 1996), which they could not have learnt from modelling the linguistic input, but instead may reflect properties of the innately specified architecture of the language system (Pinker, 1999: 208); see Haskell et al. (2003) and Ramscar and Dye (2010) for a different view. Although compounding has been examined previously in ERP studies (e.g., Koester and Schiller, 2008; MacGregor and Shtyrov, 2013), studies of the plurals-in-compounds effect using brain measures are not available. The neural correlates of the plurals-in-compounds effect and the question of whether there are any developmental changes in the brain\'s responses to contrasts such as ducks feeder vs. geese feeder have therefore remained unanswered. The present study addresses these questions by measuring ERPs from 8- to 12-year-old children as well as adults during their (silent) productions of English compounds containing (regular vs. irregular) plural modifiers.