Recently there has been a plethora of studies that have investigated the effects of computer-based instructional materials on second language (L2) learning in the classroom setting. Such computer-assisted instruction (CAI) is hypothesized to have numerous benefits over traditional instruction for L2 learning, benefits that include the provision of concurrent feedback, self-pace progress, more individual interaction with the materials, and exposure to L2 information from multiple modalities that may potentially address learners' different learning styles. Currently, there are four studies that have actually conducted empirical experiments comparing CAI with non-CAI to support their claims on the effects of computer use in grammatical exposure (Nagata, 1996; Nutta, 1998; Nutta et al., 2002; Torlakovic & Deugo, 2004). However, with careful examination, several limitations were found in these studies could potentially weaken their find ings on the effective use of computer-based instruction. Therefore, whether CAI is superior to non-CAI needs to be empirically supported by more robust findings.
In addition, the type of post-exposure task on learners' performances has not been systematically investigated even though different tasks have been used to assess learners' developing stages of cognitive processing. Hence, the present study sought to address these important issues by empirically investigating, within an attentional framework, (1) the effects of computer-centered versus teacher-centered versus learner-centered computer instruction on L2 development, (2) whether there was any differential performance due to type of post-exposure task.
Participants were first-semester students of Spanish, the Spanish verb gustar was the targeted structure and three types of assessment tasks (oral, written and recognition) were used in a pretest-posttest-delayed posttest design to measure participants' performance after instruction. The results of the study revealed that (1) there were no significant differences between types of instruction and (2) there were significant main effects for type of post-exposure task.