This article reviews research on the spatial contiguity and temporal contiguity effects. Research on these instructional design effects has focussed on the instructional benefits for novices of reducing split attention between spatially or temporally disparate but related elements of information. Meta-analytic techniques were applied to 50 independent studies yielding performance data. Major hypotheses regarding the instructional benefits of reducing split attention across time or space were supported, including the effect of a hypothesised moderator, the complexity of learning materials. The analyses indicate that, for complex learning materials in particular, increasing either the spatial or temporal contiguity of related elements of information can lead to substantial learning gains.