Figure 1.

Theoretical division of the number of items remembered into 3 separate portions: those remembered from acoustic (sound) lists regardless of the attention condition (S), those remembered from visual object arrays regardless of the attention condition (O), and those remembered using an allocation of attention that does depend on the attention condition because of a common resource such as attention (A). In unimodal verbal (or visual object) trials the contents of Area A is entirely verbal (or visual), whereas in bimodal trials, Area A can be split between verbal list items and visual objects.