Problem Representations in Multitasking: a Cognitive Bottleneck?

Most multitasking models make use of executive processes to assign resources to tasks (Kieras et al., 2000). An alternative is to have no executive, but constrain individual processes so that they share resources in a plausible way. Salvucci and Taatgen (under revision) in their theory of threaded cognition have shown how peripheral resources and declarative memory are shared between processes without an executive. In this paper we will extend this work by showing how two tasks share a resource to store the problem representation in a dual-task paradigm where either task sometimes needs a problem representation and sometimes not. Threaded cognition predicts extra interference when both tasks need a problem representation, which is what we found in the experiment.