Individual differences in multitasking: Theory and data
Many daily activities require scheduling and interleaving of multiple tasks within a limited time frame. Digital technology has become ubiquitous in our daily activities and demands and possibilities for using different forms of media in conjunction with each other have become increasingly prevalent. The amount of time people spend on everyday multitasking has dramatically increased during the past decades and these effects have been accentuated for women in their paid and unpaid work hours. Despite its ubiquitous requirement, theoretical knowledge about everyday multitasking is very limited. Why are some people better mulitaskers than others? How should work places and everyday artifacts be organized and designed to optimize benefits of everyday multitasking while minimizing its cognitive and social drawbacks? The aim of this project is to investigate cognitive mechanisms underlying everyday multitasking. The empirical studies of this project test central predictions of a framework in which multitasking is hypothesized to reflect, not only independent contributions of executive functioning, but also transformational processes of temporal relations, referred to as the spatiotemporal model of multitasking. Central predictions of this model are investigated in a series of empirical studies. The results of these studies will have both practical and theoretical implications for understanding individual differences in multiple task performance.
Final report
The aim of this project was to investigate cognitive and neural mechanisms underlying everyday multitasking. A central hypothesis of the project and its associated empirical studies was that multitasking reflects individual differences in three basic cognitive functions. In this framework, domain-specific expertise (i.e., semantic memory) and variability in prefrontally mediated executive functioning are considered as the primary sources of individual differences in multitasking. Extending earlier work, we proposed that multitasking reflects individual differences, not only in semantic memory and executive functioning, but also in spatial information processing. This new hypothesis was based on the idea that under high demands on temporal coordination (e.g., multiple tasks with narrow deadlines), individuals with efficient spatial abilities are typically better multitaskers than less spatially skilled individuals. In this view, most goal-directed tasks, including multitasking, are temporal in that scheduling, monitoring and task interleaving take place on a time scale, and that coordinating multiple goals and deadlines requires a high degree of cognitive control. In our spatial offloading hypothesis, these high demands on executive control can be alleviated either by training (so that task coordination can be guided by overlearned scripts and schemata) or that patterns of temporal relations are represented in spatial terms. Central predictions of this “time in space” offloading hypothesis were investigated in a thematically related series of empirical studies.
Central findings
The first important finding of the project was that we obtained consistent support for the spatial offloading hypothesis in that individual differences in multitasking reflect independent and selective effects of executive functioning and spatial ability. Consistent with the offloading hypothesis, individuals with efficient spatial skills (mental rotation) were better multitaskers than those with less efficient spatial abilities, and these effects were independent of individual differences in executive functioning (mainly working memory updating and inhibition). Furthermore, concurrent spatial processing impaired multitasking performance, with accentuated effects in individuals with limited spatial skills.
The second main finding of the project was that fluctuation in female sex hormones affected both spatial ability and multitasking. Specifically, females in the luteal phase (during which the estradiol level is heightened) were less accurate multitaskers than males and females in the menstrual phase (during which the estradiol level is reduced). These sex hormone-related effects on multitasking were also related to metric (coordinate), rather than categorial, spatial processing.
The third main finding of the project provided new insights into the neurocognitive mechanisms underlying multiple task performance. Using functional brain imaging, we obtained additional support for the spatial offloading hypothesis in that monitoring and coordination of temporally overlapping tasks activated the same cortical areas as in mental rotation.
Taken together, these findings provide consistent support for the hypothesis that monitoring and coordination of complex goal-directed tasks are guided by executive control functions (along with overlearned scripts and schemas), but that these cognitive control demands can be alleviated by relying on spatial relation processing.
New research questions and collateral activities
Following the predictions of the spatial offloading model, the project has generated new
research issues. Extending the original project, we have now included a developmental perspective by focusing on multiple task performance in school-aged children. Furthermore, as a logical extension of the planned work, we are also investigating individual differences in monitoring and handling delayed (rather than immediate) intentions in the context of basic mechanisms prospective memory.
Our publication strategy focused on original articles in peer-reviewed journals of cognitive sciences. We have published in major journals of psychology, including open-access outlets, and presented our findings on national and international conferences.
Central findings
The first important finding of the project was that we obtained consistent support for the spatial offloading hypothesis in that individual differences in multitasking reflect independent and selective effects of executive functioning and spatial ability. Consistent with the offloading hypothesis, individuals with efficient spatial skills (mental rotation) were better multitaskers than those with less efficient spatial abilities, and these effects were independent of individual differences in executive functioning (mainly working memory updating and inhibition). Furthermore, concurrent spatial processing impaired multitasking performance, with accentuated effects in individuals with limited spatial skills.
The second main finding of the project was that fluctuation in female sex hormones affected both spatial ability and multitasking. Specifically, females in the luteal phase (during which the estradiol level is heightened) were less accurate multitaskers than males and females in the menstrual phase (during which the estradiol level is reduced). These sex hormone-related effects on multitasking were also related to metric (coordinate), rather than categorial, spatial processing.
The third main finding of the project provided new insights into the neurocognitive mechanisms underlying multiple task performance. Using functional brain imaging, we obtained additional support for the spatial offloading hypothesis in that monitoring and coordination of temporally overlapping tasks activated the same cortical areas as in mental rotation.
Taken together, these findings provide consistent support for the hypothesis that monitoring and coordination of complex goal-directed tasks are guided by executive control functions (along with overlearned scripts and schemas), but that these cognitive control demands can be alleviated by relying on spatial relation processing.
New research questions and collateral activities
Following the predictions of the spatial offloading model, the project has generated new
research issues. Extending the original project, we have now included a developmental perspective by focusing on multiple task performance in school-aged children. Furthermore, as a logical extension of the planned work, we are also investigating individual differences in monitoring and handling delayed (rather than immediate) intentions in the context of basic mechanisms prospective memory.
Our publication strategy focused on original articles in peer-reviewed journals of cognitive sciences. We have published in major journals of psychology, including open-access outlets, and presented our findings on national and international conferences.