Split attention effect

The split-attention effect is a learning effect inherent within some poorly designed instructional materials. It is apparent when the same modality (e.g. visual and visual) is used for various types of informations within the same display. To learn from these materials learners must split their attention between these materials to understand and use the materials provided.

A visual example of split attention
Consider the graphic below from Tarmizi and Sweller (1988). They used these graphics to compare the learning that takes place given split attention conditions. Each is a possibility of how one might arrange graphical material within a lesson.

The left example produces Split attention in a learner where the right example enhances learning. The Split-attention effect is an important form of extraneous cognitive load that Instructional designers should avoid.

A Visual split-attention effect
Chandler and Sweller (1992) found through empirical study that the integration of text and diagrams reduces cognitive load and facilitates learning. They found that this effect is evident, when learners are required to split their attention between different sources of information (e.g., text and diagrams).

Split attention is important evidence of the Cognitive load theory (that the working memory load of instructional materials is important in the design of instructional materials). Chandler and Sweller (1992) found that students viewing integrated instruction spent less time processing the materials but still outperformed students in the split attention condition.

Auditory split attention
Moreno and Mayer (2000) found evidence for auditory split attention when they tested learners with both ambient environmental sounds and music as they learned from instructional materials. Animation is processed in a visual channel but must be converted the auditory channel. The extraneous cognitive load imposed by music or environmental sounds were not conducive to learning.

These researchers studied learners that learned within an environment that had additional (extraneous) environmental sounds or music and found that learners performed significantly poorer on retention and transfer tests (Moreno, 2001).