The Effects Of Word Exposure Frequency And Task-induced Involvement Load On High School Students' Incidental Vocabulary Acquisition

How to effectively improve the rate of vocabulary acquisition has been a hot issue in SLA.In the past few decades,lots of studies at home and abroad have found that word exposure frequency can make target words more obvious and that task-induced involvement load can make learners deeply process the target words,thus facilitating Incidental Vocabulary Acquisition(IVA).Nevertheless,few studies have combined the two factors to see if they will produce a ‘1+1>2' effect on IVA.And most studies on IVA at home and abroad took university students as participants while high school learners of English were not given due attention.As a result,the present study is aimed at exploring the effects of word exposure frequency and task-induced involvement load on high school students' incidental vocabulary acquisition.In the present study,152 first-year high school students in Shandong province were chosen as participants.They were from three parallel classes and received three different vocabulary tasks differ in task-induced involvement load: Group 1 was reading comprehension(involvement index=1);Group 2 was reading plus gaps-filling(involvement index=2);and Group 3 was reading plus composition-writing(involvement index=3);word exposure frequency was treated as the within-subjects factor and contained two levels: 1-OC(words occurring once in reading materials)and 5-OC(words occurring five times in reading materials).After finishing reading and vocabulary tasks,all the participants were tested the passive recall and passive recognition word knowledge of the 12 target words in both immediate posttest and delayed posttest two months later.By the software 21.0,the data from the two posttests were analyzed by employing Mixed Model ANOVA,simple effects analysis and post hoc multiple comparisons.Afterwards,a semi-structured interview was conducted and recordings of 18 interviewees were transcribed and analyzed.The major findings were: 1)immediate word gains were significantly influenced by the two factors: word exposure frequency and task-induced involvement load,and they had interactive effects on IVA,but the combination of two factors didn't produce a ‘1+1>2' effect.The reason is that vocabulary tasks have improved learners' attention on words and forced them to deeply process words,but repeated word exposures can not further improve learners' attention on words based on vocabulary tasks;2)delayed word gains were only significantly influenced by task-induced involvement load and the two factors didn't have interactive effects,which suggested the effects of word exposure frequency tended to fade over time,while task-induced involvement load had a strong and lasting effect on word retention.Therefore,task type was superior for word retention than exposure frequency;3)in perspective of passive recall and passive recognition word knowledge,repeated word exposures were conducive to vocabulary acquisition of passive recognition knowledge,while task-induced involvement load was conducive to vocabulary acquisition of passive recall knowledge.On the basis of the interview,most students reported that increasing word exposures was more conducive to strengthen form-meaning link,while reading plus vocabulary tasks focused their attention on words and forced them to deeply processing words,which was conducive to word retention.Based on the findings,some pedagogical implications for vocabulary instruction were drawn: high school teachers can repeat words to attract students' attention on words,and design different reading tasks according to specific demands.Inevitably,the study showed some limitations,such as,the limited size and scope of sample,contrived reading materials and confined dimensions of word knowledge tested.Concerning these deficiencies,future studies should select larger size and broader scope of sample,adopt more authentic reading materials and test more dimensions of word knowledge.