Explaining the split-attention effect: Is the reduction of extraneous cognitive load accompanied by an increase in germane cognitive load?

The phenomenon that the physical integration of verbal and pictorial information sources, compared to their physical separation, enhances learning is known as the split-attention effect. This paper investigates how the split-attention effect can be best explained against the background of cognitive load theory. In an experimental study, students learned about physiological processes with either an integrated or a split-source format. Secondary task performance was used to measure overall cognitive load, whereas subjective ratings were used to measure intrinsic, extraneous and germane load individually. Learners with split-source format achieved lower learning outcomes, but did not show worse secondary task performance than learners with integrated format. These results contradict the assumption that only an increase in extraneous load for learners with a split-source format mediates the split-attention effect. Mediation analyses of the subjective load ratings revealed that both, extraneous and germane load contributed to the split-attention effect. These results support the assumption that germane load also plays a crucial role in mediating the split-attention effect. (C) 2008 Elsevier Ltd. All rights reserved.