Six lexical decision experiments were conducted to examine the influence of complex structure on the processing speed of English compounds. All experiments revealed that semantically transparent compounds (e.g., rosebud) were processed more quickly than matched monomorphemic words (e.g., giraffe). Opaque compounds (e.g., hogwash) were also processed more quickly than monomorphemic words. However, when the experimental materials and/or procedure encouraged decomposition/integration, this advantage disappeared. This research suggests that morphological decomposition initiated by the existence of complex structure results in the availability of both the lexical and semantic representations of compound constituents, regardless of whether the compounds are transparent or opaque, and that meaning composition is attempted. This meaning composition further speeds up transparent compound processing beyond lexical facilitation but slows down opaque compound processing because the computed meaning for opaque compounds conflicts with the retrieved meaning.
How do people recognize morphologically complex words such as snowball and successor? One possibility is that complex words are represented in the mental lexicon as whole word units, as are monomorphemic words such as giraffe (e.g., Butterworth, 1983). However, in the past three decades, ample evidence has shown that complex words can also be accessed via their constituents ( Andrews, 1986, Andrews et al., 2004, Hyönä and Pollatsek, 1998, Juhasz et al., 2003, Libben, 1998, Marslen-Wilson et al., 1994, Pollatsek and Hyönä, 2005, Pollatsek et al., 2000, Taft, 1979, Taft, 1994, Taft and Forster, 1975, Taft and Forster, 1976 and Zwitserlood, 1994). A fundamental underlying assumption behind most theories of complex word processing is that there is a processing cost associated with using a decomposition-based route; consequently, direct access is assumed to be the faster and more efficient processing option. The current research examines the validity of this assumption in the context of compound words. Our particular aim is to evaluate the relative costs and benefits associated with the decomposition of a compound into its constituents and with the subsequent integration of those constituents.
A guiding principle behind the architectures proposed for the processing of complex words has been the balance of lexical storage vs. morphological computation. Many papers in the literature on complex word processing have been explicitly concerned with establishing how the balance of storage and computation affects lexical processing (e.g., Baayen, 2007, Bertram et al., 2000, Kuperman et al., 2010, Kuperman et al., 2009 and Libben, 2005). A wide range of theories of complex word processing have emerged as the various theories have sought to balance the demands associated with storage vs. computation, and these theories differ substantially in terms of the extent to which the morphological structure plays a role in the processing (i.e., the comprehension or production) of complex words. Some theories take a full-listing stance, in which all words are stored, and posit that morphological structure plays no (or a minimal) role (Lukatela et al., 1987 and Manelis and Tharp, 1977). Other theories posit that morphological structure is involved (Chialant and Caramazza, 1995, Dell, 1986, Frauenfelder and Schreuder, 1991, Laudanna and Burani, 1985, Laudanna and Burani, 1995, Schreuder and Baayen, 1995, Taft and Forster, 1975 and Taft and Forster, 1976). The latter theories vary in terms of the point at which the constituents’ representations become available (see Kuperman et al. (2010) for an excellent overview).
If compound word processing starts with morphological decomposition, then it seems likely that the process ends with morphological composition and semantic integration. Our data indicate that the availability of constituent representations and the semantic integration of those representations play an important role in ease of processing. The theoretical aim of the current work was to consider the consequences of this composition process and to examine the balance of storage and computation in compound word processing. Although it is commonly assumed that morphological decomposition takes time, the advantage for compound processing over monomorphemic word processing indicates that even if morphological decomposition per se is time consuming, the overall processing time for complex words is not necessarily longer than for frequency matched monomorphemic words. In particular, access to lexical entries of the constituents (which are generally higher frequency than the compound) might facilitate processing. However, in some situations, the composed meaning that results as a consequence of having the semantic and conceptual representations of the constituents available to the system might compete with the meaning retrieved from the stored representation and slow down word processing.
