First and second language visual word recognition : neighbourhood effects in Spanish and English

Current models of visual word recognition assume that the recognition of a stimulus word is affected by orthographically similar words (orthographic neighbourhood). In this thesis I explore the effects of neighbourhood on monolingual and bilingual word recognition. In particular I study the influence of Word Frequency, Neighbourhood Size (N) and Neighbourhood Frequency (NF) in English and Spanish lexical processing. N refers to the number of real words that can be created from a given word by changing one letter at a time while preserving letter position. NF refers to the frequency of the neighbours in relation to the frequency of the target word. There is a great deal of controversy as to whether orthographic neighbours facilitate or inhibit lexical processing and whether neighbourhood effects are consistent across languages. These questions are examined in four experiments carried out within the lexical decision paradigm.Experiment 1 investigates the effects of Word Frequency, N and NF with English stimuli and twenty-four English native speakers. Latency differences are not statistically reliable, but they show a tendency for both N and NF to be facilitative of lexical processing. Experiment 2 examines the same variables with Spanish stimuli and sixty-three Spanish native speakers. Data reveals null effects of N and reliable inhibitory effects of NF, with an interaction of NF with Word Frequency. In Spanish having higher frequency neighbours seems to delay lexical decision times, and this effect appears to be stronger for low frequency words. Experiment 3 explores neighbourhood effects in eighty bilingual speakers of English and Spanish with bilingual stimuli presented in two language blocks. General results show null effects of N and significant inhibitory effects of NF. Results by target language show reliable facilitative effects of N in English and highly robust inhibitory effects of NF in Spanish. Experiment 4 further investigates effects of NF in a cross-language lexical decision task with semantic translation) priming done with sixty-four bilingual speakers of English and Spanish. The purpose of the experiment is to examine the strength of cross-language priming effects under four NF conditions (NF Leaders and Nonleaders, for targets and primes). Data shows reliable priming effects in both language directions, LI to L2 and L2 to LI. Data also exhibits significant interaction between language and the priming influence of NF Leader primes and NF Nonleaders primes.The results of these experiments are discussed in the light of current experimental research and in terms of contemporary models of monolingual and bilingual lexical representation. Further questions for future research are outlined