Automaticity and speed of lexical access : acquisition and assessment

Vocabulary knowledge has been conceptualized as consisting of four components: the size of the mental lexicon, the depth or quality of knowledge of the individual lexical items in the lexicon, the degree to which those items are connected to each other (organlzation], and the speed at which those items can be retrieved and employed (e.g. Chapelle, 1998; Quian, 2002; Read, 2004; Schmitt, 2010b). There is now a considerable literature on each of the first three aspects, but lexical processing speed has hardly been explored outside the laboratory. In vocabulary acquisition research, studies have mainly focused on the acquisition of new words' form and meaning but research into the learning conditions leading to automaticity of vocabulary knowledge is still scarce. Furthermore, in the field of vocabulary testing, measures of automaticity and fluency of lexical access have seldom been used as an indication of participants' actual vocabulary knowledge of the words being assessed. This thesis attempts to address this lack in research in vocabulary acquisition and assessment. The first two studies of this thesis (Study 1 and Study 2) examine the acquisition of automaticity in the language classroom, comparing the effectiveness of two different approaches, i.e. incidental learning and explicit teaching. Results of these studies show that, the incidental approach does not lead to a significant improvement in the speed and automaticity of learners' lexical decisions in any of the measures used, i.e. reaction time (RT) and coefficient of variation (CV). However, with the explicit treatment learners' lexical decisions are not only faster but also more automatic, as measured by the CV. Results of these two acquisition studies show that automaticity of vocabulary knowledge can benefit from classroom instruction, although it might need more engaged, explicit exposure. The last two studies of this thesis (Study 3 and Study 4) examine the use of measures of RT to assess the veracity of learners' vocabulary knowledge and the use of that information to score Yes-No vocabulary size tests. Results of these last two studies show that RT carries important information about learners' accuracy and veracity of responses in vocabulary tests. These studies also present a new approach that uses this RT information to score Yes- No vocabulary size tests and that can help to make the test more valid. Overall, results of the studies presented in this thesis point out the importance of researching the acquisition of automaticity in instructional settings and the use of the time element in vocabulary tests to assess learners' vocabulary knowledge.EThOS - Electronic Theses Online ServiceGBUnited Kingdo