The problem state: A cognitive bottleneck in multitasking.

Abstract

The main challenge for theories of multitasking is to predict when and how tasks interfere. Here, we focus on interference related to the problem state, a directly accessible intermediate representation of the current state of a task. On the basis of Salvucci and Taatgen's (2008) threaded cognition theory, we predict interference if 2 or more tasks require a problem state but not when only one task requires one. This prediction was tested in a series of 3 experiments. In Experiment 1, a subtraction task and a text entry task had to be carried out concurrently. Both tasks were presented in 2 versions: one that required maintaining a problem state and one that did not. A significant overadditive interaction effect was observed, showing that the interference between tasks was maximal when both tasks required a problem state. The other 2 experiments tested whether the interference was indeed due to a problem state bottleneck, instead of cognitive load (Experiment 2: an alternative subtraction and text entry experiment) or a phonological loop bottleneck (Experiment 3: a triple-task experiment that added phonological processing). Both experiments supported the problem state hypothesis. To account for the observed behavior, computational cognitive models were developed using threaded cognition within the context of the cognitive architecture ACT-R (Anderson, 2007). The models confirm that a problem state bottleneck can explain the observed interference.

Strategic Reasoning: Building Cognitive Models from Logical Formulas

“…Consequently, if a model has to keep track of more than one piece of information, it has to move the pieces of information back and forth between two important modules: declarative memory and the problem state. Moving information back and forth comes with a time cost, and could cause a so-called cognitive bottleneck (Borst et al 2010). …”

Using model-based functional MRI to locate working memory updates and declarative memory retrievals in the fronto-parietal network

“…Its function is similar to the focus of attention in current working memory theories (17), and it can hold only one coherent chunk of information (18). We use the problem state module to locate working memory updates.…”

Peripheral interaction: characteristics and considerations

“…Multiple threads can be active at the same time, for example, we can easily drive a car (thread one) and listen to the radio (thread two) at the same time, as also evident from multiple resource theory [19]. Next to the socalled central procedural resource, which coordinates the execution of multiple threads, these threads can make use of various 'peripheral resources,' such as visual resources, motor resources or memory resources [20]. As described by threaded cognition theory [18], each particular resource can only be used by one thread at a time.…”

“…For example, since one can only look at one visual object at the time, a person who is driving while using a navigation system can only look at either the road or the navigation system's display. When both require visual attention, a bottleneck [20] occurs and one of these two threads must wait before the visual resource is free. Therefore, the extent to which two activities can be performed in parallel depends on their stage of execution and the particular resources they require.…”