Why Does Dual-Tasking Hamper Implicit Sequence Learning?

Abstract

Research on the limitations of dual-tasking might profit from using setups with a predictable sequence of stimuli and responses and assessing the acquisition of this sequence. Detrimental effects of dual-tasking on implicit sequence learning in the serial reaction time task (SRTT; Nissen & Bullemer, 1987)-when paired with an uncorrelated task-have been attributed to participants' lack of separating the streams of events in either task. Assuming that co-occurring events are automatically integrated, we reasoned that participants could need to first learn which events co-occur, before they can acquire sequence knowledge. In the training phase, we paired an 8-element visual-manual SRTT with an auditory-vocal task. Afterwards, we tested under single-tasking conditions whether SRTT sequence knowledge had been acquired. By applying different variants of probabilistic SRTT-tone pairings across three experiments, we tested what type of predictive relationship was needed to preserve sequence learning. In Experiment 1, where half of the SRTT-elements were paired to 100% with one specific tone and the other half randomly, only the fixedly paired elements were learned. Yet, no sequence learning was found when each of the eight SRTT-elements was paired with tone identity in a 75%-25% ratio (Experiment 2). Sequence learning was, however, intact when the 75%-25% ratio was applied to the four SRTT target locations instead (Experiment 3). The results suggest that participants (when lacking a separation of the task representations while dual-tasking) can learn a sequence inherent in one of two tasks to the extent that across-task contingencies can be learned first.

Learning of across- and within-task contingencies modulates partial-repetition costs in dual-tasking

“…The findings revealed that implicit learning was preserved for the fixedly, but hampered for the variably paired SRTT-tone combinations. Again, this finding suggests that the participants integrate the stimuli of the two tasks before they then can learn something about the sequence built into the SRTT (see also Röttger et al, 2021).…”

“…Several findings in the field of dual-tasking suggest that the participants tend to integrate the two tasks within a trial into one single task-set when the stimuli of these tasks are presented in temporal proximity (Schumacher & Hazeltine, 2016 ; Röttger et al, 2019 , 2021 ; Schmidtke & Heuer, 1997 ; Zhao et al, 2020 ). The goal of the current study was to examine whether the generation of joint memory episodes might be a conceivable mechanism underlying task integration (Logan, 1988 ).…”

“…First, event files are thought to be rather short-lived, and second, the partial-repetition costs depend on feature-code overlap between tasks. By contrast, task integration in dual-tasking presupposes survival across trial boundaries (e.g., Moeller & Frings, 2017 ; Zhao et al, 2020 ), and seems to occur even when the tasks consist of a visual-manual and an auditory-vocal task which do not overlap in any feature code (Röttger et al, 2019 , 2021 ; Schumacher & Schwarb, 2009 ).…”

“…Unbeknownst to the participants, the marked screen locations follow a regular sequence. Even though implicit learning is generally a robust phenomenon (e.g., Reber, 1993), it is often found to be hampered in dualtasking, especially if the stimuli in the other task are drawn randomly (Hsiao & Reber, 2001;Rah et al, 2000;Röttger et al, 2019Röttger et al, , 2021Schmidtke & Heuer, 1997;Schumacher & Schwarb, 2009;Zhao et al, 2020).…”

The State-of-the-art of Research into Human Multitasking: An Editorial

“…However, a performance-reducing influence of the secondary task was not found during sequence retrieval, which the authors explained with the availability of an abstract representation of the sequence, which makes the primary task invulnerable to dual-tasking interference. Röttger et al (2021) investigated the disruption of learning in a visual-manual serial reaction time task by interference with a secondary auditory-vocal task. By creating probabilistic pairings between stimulus features in the serial-reaction time task and in the secondary task, the authors demonstrated that across-task contingencies facilitate learning in the primary task despite any imposed dual-task demands.…”