The purpose of this dissertation is to investigate the extent to which there is consistent evidence pertaining to the prime lexicality effect. Theoretical claims about the nature of this effect, in which masked nonword form primes produce greater facilitation than word form primes, have been hotly debated in the masked priming literature. Here, there are two major conflicting accounts of visual word recognition to consider. Cascaded activation approaches such as the Interactive Activation model rely on competition between word units to account for word recognition. This view predicts inhibitory effects for word form primes due to competition between word units for the prime and target. In contrast, proponents of the Search Model have maintained that elements in the process of verifying visual input suggest that word primes should produce neither facilitatory nor inhibitory effects during masked presentation. Evidence that is consistent with both approaches has been reported in the literature. A 1998 study by Forster and Veres looked at long words using a masked lexical decision task and demonstrated strong facilitation from nonword primes and no effect for word primes. A 2006 paper for Davis and Lupker, however, reported that the nonword prime facilitation that they observed using the same task was accompanied by strong word prime inhibition. The presence of this inhibitory effect seems to support the interactive activation account, but it remains unclear why inhibitory effects such as these were not seen in the Forster and Veres work. The present study sought to explore the reliability of the effects that are generated by word form primes. In particular, the different types of stimuli used in the conflicting papers (i.e. long versus short items) were contrasted. Evaluations regarding their relative discrimination difficulty and performance during masked lexical decision were conducted. The investigation revealed that there is indeed a difference between the output provided by those different stimulus types and that context effects emerge when they are presented together in the same experiment. The implications of these findings for the various views on visual word recognition are discussed.

Most research in word recognition uses words that already exist in the reader's lexicon, and it is therefore of interest to see whether newly learned words are represented and processed in the same way as already known words. For example, are newly learned words immediately represented in a special form of lexical memory, or is there a gradual process of assimilation? As for L2 language learners, are newly learned words incorporated into the same processing system that serves L1, or are they represented quite independently?The current study examines this issue by testing for the existence of the Prime Lexicality Effect (PLE) observed in masked priming experiments (Forster & Veres, 1998). Strong form priming was found with nonword primes (e.g., contrapt-CONTRACT), but not with word primes (e.g., contrast-CONTRACT). This effect is generally assumed to result from competition between the prime and the target. So if the readers had been trained to treat "contrapt" as a new word, would it now function like a word and produce much weaker priming? Elgort (2007) demonstrated such an effect with unmasked primes with L2 bilinguals. The current study investigates the PLE in both L1 and L2 bilinguals under different training conditions. When the training program involves mere familiarization (learning to type the words), a PLE was found with visible primes, but not with masked primes, which suggests that unmasked PLE is not the best indicator of lexicalization. In the case of "real" acquisition where the new word is given a definition and a picture of the object it refers to, and learning is spread over two weeks, a clear PLE was obtained. However, when the same experiment was carried out on Chinese-English bilinguals using the same English materials, completely opposite results were obtained. The learning enhanced priming, rather than reducing it, suggesting that the L2 lexicon might differ qualitatively from the L1 lexicon. The implications of these results for competitive theories of lexical access are discussed, and alternative explanations are considered.