In this paper, a model-based analysis method for fMRI is used with a high-level symbolic process model. Participants performed a triple-task in which intermediate task information needs to be updated frequently. Previous work has shown that the associated resource – the problem state resource – acts as a bottleneck in multitasking. The model-based method was used to locate the neural correlates of ‘problem state replacements’. To analyze the fMRI data, we fit the computational process model to the behavioral data and regressed the model’s activity against the fMRI data. The brain region responsible for the temporary representation of problem states, the inferior parietal lobule, and the brain region responsible for long-term storage of problem states, the inferior frontal gyrus were thus identified. These results show that model-based fMRI analyses can be performed using high-level symbolic cognitive models, enabling fine-grained exploratory fMRI research.

When people have to store intermediate results for multiple tasks concurrently, performance decreases considerably as opposed to when at most one intermediate result has to be stored. Borst, Taatgen and Van Rijn (2010) have shown that a multitasking bottleneck associated with intermediate problem representations can account for this effect. This study investigates whether representing problem representations externally reduces the interference. To this end we extended the experiment in Borst et al. (2010) with a version that required no problem representation. The results show that there is an over-additive increase in response times when both tasks need to store an intermediate representation, as compared to a situation in which at most one task requires an intermediate representation, either because no intermediate representation is needed, or because the intermediate representation is available on the screen. These results suggest that multitasking performance can be improved by presenting intermediate representations in the environment.

Distinct contributions of the caudate nucleus, rostral prefrontal cortex, and parietal cortex to the execution of instructed tasks

Distinct contributions of the caudate nucleus, rostral prefrontal cortex, and parietal cortex to the execution of instructed tasks