Optimierung von Aufgabenkoordination in Doppelaufgaben: Allgemein- und entwicklungspsychologische Aspekte der Gedächnishypothese
Final Report Abstract
The project investigated mechanisms that are involved in the practice-related optimization of dual-task (DT) performance. It starts from the observation that performing two tasks simultaneously usually leads to DT costs compared to the isolated performance of the two tasks and that these DT processing can be optimized as a result of extended practice. In particular, we investigated practicerelated mechanisms of DT optimization which are specified by the memory hypothesis. As a central assumption of this hypothesis, DT performance improves with practice because of an efficient and conjoint instantiation of task relevant information in working memory (WM) at the onset of a DT trial, which includes the task sets of the two component tasks of the DT situation. As a result, the coordination of component task processing becomes improved in those DT situations that include a bottleneck interrupting the task streams during DT processing. We investigated the validity of the memory hypothesis by testing three critical sub-predictions of that hypothesis: 1) A first set of studies tested a prediction about the preconditions for successful acquisition and transfer of coordination skills due to practice as specified by the memory hypothesis. The results showed that (as predicted) only extended DT training (but not single-task training) can result in efficient and conjoint instantiation of task information of both tasks already at the onset of DT trials. By contrast, single-task practice does not lead to that. Further studies specified that also the mixed presentation of two component tasks with changing stimulus-response mappings during training can lead to successful acquisition of coordination skills if task order during is not predictable for participants during training. 2) Further, we investigated the role of component task complexity for the practice-related optimization of task coordination in DT situations. According to the memory hypothesis, DT situations with complex component tasks should lead to a disappearance of DT-training related benefits compared to training with single-task situations. That prediction could be proved in several experiments, which supports a main part of the memory hypothesis, namely that the instantiation of component task sets during DT training is operated by a WM with limited processing and storage capacity. Given the capacity limitation of the WM, the proposed mechanism for improving DT coordination cannot work if the component tasks exceed the capacity of the WM used for maintaining task information during DT processing. 3) The memory hypothesis of DT training could also be proved in several studies that investigated a prediction about the impact of age-related decline in WM capacity on DT optimization. These studies investigated older participants as an example-population for participants suffering from decreased WM capacity. Since DT training effects should rely on WM resources, the memory hypothesis predicts that older compared with younger participants should capitalize to a lesser degree on DT training. Thus, the memory hypothesis does not preclude training-related improvements in older participants, but it predicts that older participants show reduced training gains for improved DT coordination after DT training compared to the latter population. Several studies showed that older subjects are indeed capable of training-related improvements in DT performance, however, the degree of training-related improvements is smaller in older than in younger subjects. More detailed analyses of the processing architecture showed a processing scheduling in older participants’ DT processing that is similar to that in younger participants but with less probability of conjoint instantiation of two task representations in WM. In situations with less complex component tasks, older subjects proved to be capable of a similar optimization of DT coordination just as the younger adults showed with more complex component tasks supporting the role of age-related WM decline for DT training. Together, the findings of three lines of experimentation proved the validity of the main predictions of the memory hypothesis for practice-related improvement of DT coordination. The results support the idea that the proposed mechanism of an efficient and conjoint instantiation of component task information into WM represents an important mechanism of practice-related improvement of DT processing. The assumption of that mechanism needs to be added to earlier models on DT training, which assume automatization and processing stage shortening as main mechanisms for practice-related improvements of DT processing.
Publications
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(2012). Age- and practice-related influences on dual-task costs and compensation mechanisms under optimal conditions for dual-task performance. Aging, Neuropsychology & Cognition, 19, 222-247
Strobach, T., Frensch, P. A., Müller, H., & Schubert, T.
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(2012). Investigation on the improvement and transfer of dual-task coordination skills. Psychological Research, 76, 794-811
Strobach, T., Frensch, P. A., Soutschek, A., & Schubert, T.
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(2012). Testing-the-limits of optimizing dual-task performance in younger and older adults. Frontiers in Human Neuroscience, 6, 39
Strobach, T., Müller, H.J., Frensch, P.A. & Schubert, T.
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(2013). Effects of extensive dual-task practice on processing stages in simultaneous choice tasks. Attention, Perception, & Psychophysics, 75(5), 900-920
Strobach, T., Liepelt, R., Pashler, H., Frensch, P., & Schubert, T.
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(2014). Practice-related optimization and transfer of executive functions: A general view and a specific realization of their mechanisms in dual tasks. Psychological Research, 78, 836-851
Strobach, T., Salminen, T., Karbach, J. & Schubert, T.
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(2015). Does Initial Performance Variability Predict Dual-Task Optimization with Practice in Younger and Older Adults? Experimental Aging Research, 41(1), 57-88
Strobach, T., Gerstorf, D., Maquestiaux, F., & Schubert, T.
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(2015). Evidence for the acquisition of dual-task coordination skills in older adults. Acta Psychologica, 160, 104-116
Strobach, T., Frensch, P., Müller, H., & Schubert, T.
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(2016). Age-specific differences of dual n-back training. Aging, Neuropsychology and Cognition, 23, 18-39
Salminen, T., Frensch, P., Strobach, T., & Schubert, T.
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(2016). Mechanisms of Practice-Related Reductions of Dual-Task Interference with Simple Tasks: Data and Theory, 13(1), 28-41
Strobach, T. & Schubert, T.
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(2017). No evidence for task automatization after dual-task training in younger and older adults. Psychology and Aging, 32(1), 28-41
Strobach, T., & Schubert, T.
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(2017). Transferability of Dual-Task Coordination Skills after Practice with Changing Component Tasks. Frontiers in Psychology, 8, 956
Schubert, T., Liepelt, R., Kübler, S., & Strobach, T.
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(2018). Practice-related optimization of dual-task performance: Efficient task instantiation during overlapping task processing. Journal of Experimental Psychology: Human Perception and Performance, 44(12), 1884
Schubert, T., & Strobach, T.
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(2019). Cross-modal transfer after auditory task-switching training, Memory & Cognition, 47(5), 1044-1061
Kattner, F., Samaan, L., Schubert, T.
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(2020). Cross-Modal Transfer Following Auditory Task-Switching Training in Old Adults. Frontiers in Psychology 12, 486
Toovey, B.R.W., Kattner, F., Schubert, T.
