Abstract
Continuous motor tasks like walking have the potential to allow a dynamic allocation of processing resources when interrupted by intermittent cognitive tasks. The degree to which a successful interleaving of processing streams of both tasks is possible may depend on the temporal regularity of events. Fifteen subjects participated in an experiment where we systematically manipulated the regularity of stimulus onsets in a 2-back task relative to the step cycle. We tested three conditions where stimulus onset was always synchronous to a defined event in the stride (right heel strike, left heel strike, and midway between two heel strikes) and two conditions where the temporal location of the stimulus shifted from stride to stride. In order to test for potential effects of task difficulty, we also manipulated walking speed. We measured reaction times, accuracy of the reactions and several measures describing motor performance. There was no sign of task interference in these measures when stimuli always appeared at the same relative location within the step cycle. However, we observed prolonged reaction times when the stimulus came up earlier than expected. Surprisingly, in the other non-regular regime, where the stimulus appeared later than expected, reaction times were fastest. We interpret this result in the light of a prescheduled allocation of processing resources that is linked to the cyclic profile of processing requirements of the motor task.
Highlights
Humans are limited in their ability to handle multiple tasks in parallel
Dual-task interference in terms of performance decrements is observed when tasks keep going for longer periods of time, like in many postural or locomotion tasks
We introduce the additional assumption that processing requirements for the motor task vary across the cycle and that this regime is strictly temporally linked to the ongoing cyclic activity
Summary
At least one of the tasks shows performance decrements compared to a single-task control condition. Explanations commonly refer to a conflict at a central level of processing, where tasks compete for limited processing resources. This interference has been widely demonstrated in speeded reaction-time (RT) tasks where stimuli are presented in close temporal succession (Koch et al 2018). Given the close temporal constraints of speeded RT tasks, subjects are very limited in implementing individual strategies in the temporal control of processing activities. Given the strong empirical evidence for these phenomena, comparatively little is known about the underlying interference at the level of control processes (Wollesen & Voelcker-Rehage 2014)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
