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Inter-individual differences in multitasking: Prioritisation and conceptualization as determinants of efficient multitasking (2015-2018; 2018-2021)


 Stefan Künzell

Prof. Dr. Stefan Künzell                         

Principal Investigator

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 Markus Raab

Prof. Dr. Markus Raab               

Principal Investigator

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 Harald Ewolds

Harald Ewolds

PhD Candidate

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 Laura Bröck

Dr. Laura Bröker

Post-doctoral Fellow

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 Rita de OliveiraRita de Oliveira

Dr. Rita F. de Oliveira

Project Collaborator

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Abstract (2018-2021)

Multitasking is the simultaneous execution of two tasks. In our research proposal we analyze the flexibility of performance in dual-tasking. For this purpose we combine a sensorimotor and a cognitive task. In the first funding period we found out that dual task costs are reduced if tasks are predictable, both by perception and by knowledge. However, performance improved in the predictable tasks only, the other task remained uninfluenced, except features of the tasks are mutually dependent. We assume two reasons for these findings. If only one task is predictable, this task could be prioritized. In case of mutually dependence, the tasks could be conceptualized as a single (super-)task. In our proposal for the second funding period, we investigate these two strategies.

In Project A, we analyze the influence of individual predictors on prioritization in dual-tasking and in Project B the influence of task conceptualization on dual task performance. In our research series we use the typing-while-tracking paradigm (Janssen & Brumby 2015, PLoS ONE, 10: e0130009) for our experiments, where participants have to type a line of digits with their left hand while they have to keep a moving cursor in the middle of a target with their right hand. In Project A, phase 1, we manipulate behavioural consequences by varying a payoff function and analyze, if individual differences in risk-tendency, approach-avoidance, starting preferences of sustained attention between participants influence individual prioritisation of a task. In phase 2, following decision field theory, we develop and validate a model which predicts prioritisation from these individual differences.

In Project B, phase 1, we analyze the influcence of task conceptualization on dual task performance by manipulating instructions (one or two tasks) and Feedback (cumulated or separated Feedabck). In phase 2 we test if conceptualisation is a useful strategy to cope with multitasking demands an look for individual differences in conceptualization abilities.


Abstract (2015-2018)

Multitasking occurs when two or more tasks are executed simultaneously. Studies exploring central processes of multitasking have focused on the parallel execution of two reaction time (RT) tasks, where it is regularly observed that performance decreases in dual-task condition compared to single-task conditions. While these experimental paradigms successfully provoke dual-task interferences and suggest the presence of a central bottleneck, they are unsuitable to investigate flexibility and plasticity of multitasking behavior. In RT experiments, it is essential that neither the stimulus nor the response can be predicted, because predictability would disrupt the validity of RT measurement. However, we argue that prediction plays a crucial role in coping with multiple tasks. In contrast to the experimental design outlined above, prediction and planning of tasks are common ways to control movements in everyday life. In our project we will investigate how predictability would influence performance in multitask situations. We suggest that dual-tasks can be successfully executed when at least one of the tasks is well learned and the situation and the motor outcome are predictable. To test this we are implementing a tracking task in which participants follow a target dot on an invisible tracking path with a joystick. Predictability is manipulated either by explicitly given or implicitly gained knowledge about a repeating middle segment or by visualizing a path segment of a predefined length that varies in different experimental conditions. As a second task, we introduce an auditory task in which participants respond to a target sound by pressing a pedal. Similarly to the first task, predictability will be manipulated. Sounds will be presented either in randomized or organized order or will be temporally correlated with the occurrence of turns in the tracking path. In a later stage of the project, the results will be compared to dual-task performance in a driving simulator. Similar to the first experiment, a winding road will vary in length of the visible path ahead. This will be akin to driving on a foggy night; the headlights in the car will illuminate different portions of the path ahead. We predict that both implicit and explicit knowledge, dual-task practice, predictability by perception (through varying path lengths) as well as increasing predictability in the second task will enhance multitask performance in both the tracking and the driving tasks. In a final step, we will also examine the weighted influence of both prior knowledge and perception. In summary, our experiments will show that plasticity in multitasking correlates with the degree of predictability of each single task involved.


Project Output

Broeker, L., Ewolds, H., Oliveira, R. F. de, Künzell, S., & Raab, M. (2021). The impact of predictability on dual-task performance and implications for resource-sharing accounts. Cognitive Research: Principles and Implications, 6(1), 1.

Ewolds, H., Broeker, L., Oliveira, R. F. de, Raab, M., & Künzell, S. (2021). Ways to Improve Multitasking: Effects of Predictability after Single- and Dual-Task Training. Journal of Cognition, 4(1), Article 4.

Broeker, L., Ewolds, H., Oliveira, R. F. de, Künzell, S. & Raab, M. (2020). Additive Effects of Prior Knowledge and Predictive Visual Information in Improving Continuous Tracking Performance. Journal of Cognition, 3(1), Artikel 40.

Broeker, L., Haeger, M., Bock, O., Kretschmann, B., Ewolds, H., Künzell, S. & Raab, M. (2020). How visual information influences dual-task driving and tracking. Experimental brain research, 238(3), 675–687.

Ewolds, H., Broeker, L., Oliveira, R. F. de, Raab, M. & Künzell, S. (2020). No impact of instructions and feedback on task integration in motor learning. Memory & Cognition. Vorab-Onlinepublikation.

Künzell, S., Bröker, L., Dignath, D., Ewolds, H., Raab, M., & Thomaschke, R. (2018). What is a task? An ideomotor perspective. Psychological Research, 81(1), 4-11. doi: 10.1007/s00426-017-0942-y

Bröker, L., Liepelt, R., Poljac, E., Künzell, S., Ewolds, H., de Oliveira, R. F., & Raab, M. (2018). Multitasking as a choice problem. Psychological Research, 81(1),12-23. doi: 10.1007/s00426-017-0938-7

Broeker, L., Kiesel, A., Aufschnaiter, S., Ewolds, H., Gaschler, R., Haider, H., Künzell, S., Raab, M., Röttger, E.,
Thomaschke, R. & Zhao, F. (2017). Why prediction matters in multitasking and how predictability can
improve it. Frontiers in psychology, 8:2021. doi: 10.3389/fpsyg.2017.02021.

De Oliveira, R. F., Raab, M., Hegele, M., & Schorer, J. (2017). Task integration facilitates multitasking. Frontiers in Psychology, 8.

Ewolds, H. E., Bröker, L., Oliveira, R. F. de, Raab, M., & Künzell, S. (2017). Implicit and Explicit Knowledge Both Improve Dual Task Performance in a Continuous Pursuit Tracking Task. Frontiers in Psychology, 8, 6. doi:

Künzell, S., Sießmeir, D., & Ewolds, H. (2017). Validation of the Continuous Tracking Paradigm for Studying Implicit Motor Learning. Experimental Psychology, 63(6), 318–325.

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