Cognitive load theory has been utilized by second language acquisition (SLA) researchers to account for differences in learner performance with regards to different learning tasks. Certain instructional designs were shown to have an impact on cognitive load and working memory, and this impact was found to be accentuated in a multimedia environment where there is a variety of interacting elements and tools that can lead to cognitive overload and consequently reduced learning outcomes. This study investigated the influence of split-attention and integrated instructional formats on students’ cognitive load and how they might facilitate second language online reading and vocabulary learning. Twenty English as a Second Language (ESL) intermediate students studying at an Australian language institution were randomly assigned to four conditions: SAND (Split-Attention No Dictionary), SAOD (Split-Attention with Online Dictionary), IFND (Integrated Format No Dictionary), and IFOD (Integrated Format with Online Dictionary). Subjects were asked to complete an online reading comprehension task in which subjects tested under the SAND and SAOD conditions were exposed to a typical reading text followed by comprehension questions, whereas subjects in the IFND and IFOD conditions were exposed to a reading text where the comprehension questions were physically inserted within the reading text. Under the SAOD and IFOD conditions, subjects had access to an online dictionary. Results showed that the integrated reading format was found to facilitate students’ reading comprehension more than the split-attention format. Also, students who had access to the online dictionary in the SAOD and IFOD groups performed better on the vocabulary test, but spent more time on the reading task than the other two groups. Furthermore, participants in the split-attention format group looked up more words than their counterparts in the integrated format group. The results of the present study have certain implications for multimedia instructional designers and ESL teachers.
