5. Both de Graaff (1997) and Rosa & Leow (2005) studied the relationship between instruction and SLA, and both showed that instruction affected SLA. However, there are many differences between the two studies. Discuss the major differences between the two studies in terms of a) their specific research questions, b) the independent variables and their manipulations, c) how acquisition was measured, and d) their conclusions.
De Graaff asked “Does explicit knowledge facilitate acquisition?†De Graaff’s study has a 2 x 2 x 3 design, namely Explicit vs. Implicit group x Timed vs Un-timed x Task Type (3 types). In de Graaff’s study, acquisition is measured by a grammatical judgment with time pressure, a grammatical judgment without time pressure, a translation, and a fill-in-the-blanks test. De Graaf concluded that explicit instruction will improve proficiency on test, though the hypothesis regarding complex, time-constrained, and syntactic nature of the test items remained unproven.
Rosa & Leow asked, “Do different learning conditions affect awareness? And does awareness affect learning outcomes (on two different types of tests, namely multiple-choice recognition and controlled production)?†Rosa & Leow’s study has a 2 x 2 x 3 design, namely task essential(+/-) x explicit pretask (+/-) x immediate feedback (- / +explicit / +implicit). In Rosa & Leow’s study, acquisition is measured by multiple-choice recognition tests and controlled production tests, one given immediately following the treatment and one delayed. Rosa & Leow concluded that “learners who had received explicit information on their target structure had a clear tendency to report higher levels of awareness†than those who received less explicit information. Further, the study concluded that those with greater awareness (at “understanding†level) did score higher than those at lower awareness levels.