Developmental Science 10:6 (2007), pp 794–813 DOI: 10.1111/j.1467-7687.2007.00628.x © 2007 The Authors. Journal compilation © 2007 Blackwell Publishing Ltd, 9600 Garsington Road, Oxford OX4 2DQ, UK and 350 Main Street, Malden, MA 02148, USA. Blackwell Publishing Ltd PAPER Development of sentence interpretation The development of sentence interpretation: effects of perceptual, attentional and semantic interference Robert Leech, 1 Jennifer Aydelott, 1 Germaine Symons, 2 Julia Carnevale 3 and Frederic Dick 4 1. School of Psychology, Birkbeck College, London, UK 2. Department of Logic, Philosophy and Scientific Method, London School of Economics, UK 3. Harvard Medical School, Cambridge, MA, USA 4. CRL, University of California, San Diego, USA Abstract How does the development and consolidation of perceptual, attentional, and higher cognitive abilities interact with language acquisition and processing? We explored children’s (ages 5–17) and adults’ (ages 18–51) comprehension of morphosyntactically varied sentences under several competing speech conditions that varied in the degree of attentional demands, auditory masking, and semantic interference. We also evaluated the relationship between subjects’ syntactic comprehension and their word reading efficiency and general ‘speed of processing’. We found that the interactions between perceptual and attentional processes and complex sentence interpretation changed considerably over the course of development. Perceptual masking of the speech signal had an early and lasting impact on comprehension, particularly for more complex sentence structures. In contrast, increased attentional demand in the absence of energetic auditory masking primarily affected younger children’s comprehension of difficult sentence types. Finally, the predictability of syntactic comprehension abilities by external measures of development and expertise is contingent upon the perceptual, attentional, and semantic milieu in which language processing takes place. Introduction Children’s syntactic development is often characterized as a rapid and relatively effortless process of establishing or fixing ‘parameters’ for a finite set of syntactic rules (Chomsky, 1980; Caplan & Waters, 1999; Crain & Pietroski, 2001; Foder, Bever & Garrett, 1974; Grodzinsky, 2000; Pinker, 1994; van der Lely, 2005). This approach empha- sizes the child’s early and fast-emerging competence in computing the symbolic relations between syntactic cues, and often relegates to ‘performance’ the role auditory percep- tion and attentional control plays in complex language comprehension. In contrast, emergentist (MacWhinney, 1999) or connectionist (Thomas & Karmiloff-Smith, 2003) approaches tend to emphasize slower-emerging interactions between perceptual, cognitive, and linguistic processes over development. On such accounts, the processing of language is not carried out by language-dedicated modules; rather, language is inextricably enmeshed with ‘lower-level’ sensorimotor processes. Here, patterns of behavior that may appear rule-governed instead emerge through the interaction of acoustical, phonological, lexical, and syntactic cues (Monaghan, Chater & Christiansen, 2005). The development of language therefore involves not just acquiring words and grammatical structures but also developing and refining a range of auditory and attentional abilities throughout childhood and into adolescence. This is in marked contrast to the ‘continuity hypothesis’ whereby children attain syntactic mastery around 4 to 5 years of age – see Tomasello, 2000, for an overview and critique. Accordingly, recent research suggests that the successful acquisition of language may be contingent upon the development of fine motor and auditory skills (Alcock, Passingham, Watkins & Vargha- Khadem, 2000a, 2000b; Bishop, 2002; Briscoe, Bishop & Norbury, 2001; France, Rosner, Hansen, Calvin, Talcott, Richardson & Stein, 2002; Hill, Hogben & Bishop, 2005), as well as on domain-general attentional processes (Smith, Jones & Landau, 1996). Deficits in motor and auditory abilities and attentional control have been implicated in Address for correspondence: Robert Leech, School of Psychology, Birkbeck College, Malet Street, London WC1E 7HX, UK; e-mail: r.leech@bbk.ac.uk