Cognitive load and learner expertise : Split-attention and redundancy effects in reading compreh<nsion tasks with vocabulary definitions

In 3 experiments, the author examined the effects of cognitive load management by inserting vocabulary definitions into reading passages. In Experiment 1, for 5th-grade readers of English as a 2nd language (ESL), vocabulary definitions integrated within a passage (integrated format) improved comprehension (high-level processing), whereas a separate vocabulary list (separated format) improved vocabulary learning (low-level processing). In Experiment 2, for 8th-grade ESL learners, the separated format improved comprehension, whereas the integrated format improved vocabulary learning. In Experiment 3, with university students, there was a Format x Level interaction effect similar to that in Experiment 2. Efficiency of instruction depends partly on its ability to manage cognitive load. An identical presentation format may facilitate learning by reducing cognitive load but may interfere with learning through either split-attention or redundancy effects, depending on learner expertise. For less experienced readers, the integrated format reduced split-attention effects for comprehension but induced redundancy effects for vocabulary learning. For more experienced readers, the integrated format induced redundancy effects and hampered performance in comprehension.