The Effects Of Visual Input Enhancement On Chinese Middle School Students’Acquisition Of English Present Perfect Tense

Foreign researchers have begun to investigate the potential effectiveness of visual input enhancement on SLA since1990s, which emphasizes the "noticeability" of input by means of bolding, color-coding, shading or capitalizing certain language forms in order to increase the chances of being turned into intake. But studies based on this theoretical framework have given unconvincing and even conflicting results. Some proved the positive effects of textual enhancement on acquisition (e.g. Doughty1991; Shook1994; Jourdenais et al.1995), some argued that textual enhancement did have partial effects on acquisition (e.g. Alanen1995; White1998), while others showed no effects on acquisition (e.g. Izumi2002; Leow2001; Wong2003). Besides, exploring the effects of different types of input enhancement techniques (such as textual enhancement, grammar instruction and so on) on SLA is another hot topic that has sparked a great deal of interest in the field of SLA abroad (e.g. Fahim&Vaezi2011; Nahavandi&Mukundan2011), yet, comparatively few relevant studies have been conducted by Chinese researchers.Based on the Noticing Hypothesis and input enhancement, this study tries to investigate the potential effects of visual input enhancement (bolding is adopted in this study to highlight the target language form) on the acquisition of English present perfect tense under different conditions by students in Grade8from a middle school in Changsha, and meanwhile compare the different effects on the acquisition of the target language form between visual input enhancement and grammar instruction, attempting to answer the following research questions:1) What are the effects of visual input enhancement on Chinese middle school students’acquisition of English present perfect tense?2) What are the effects of visual input enhancement on middle school students’acquisition of the target language form under the condition that the target form has already been explicitly instructed?3) Which technique, visual input enhancement or grammar instruction, better facilitates Chinese middle school students’acquisition of the target language form?The major findings of this study are presented as follows:1) Visual input enhancement has positive effects on Chinese middle school students’acquisition of English present perfect tense, especially for the acquisition of implicit knowledge, the effects are significant.2) Visual input enhancement has no significant effects on middle school students’acquisition of the target language form under the condition that the target form has already been explicitly instructed.3) Grammar instruction can facilitate Chinese middle school students’acquisition of the target language form more effectively than visual input enhancement.