Response-code conflict in dual-task interference and its modulation by age

Abstract

Difficulties in performing two tasks at once can arise from several sources and usually increase in advanced age. Tasks with concurrent bimodal (e.g., manual and oculomotor) responding to single stimuli consistently revealed crosstalk between conflicting response codes as a relevant source. However, how this finding translates to unimodal (i.e., manual only) response settings and how it is affected by age remains open. To address this issue, we had young and older adults respond to high- or low-pitched tones with one (single task) or both hands concurrently (dual task). Responses were either compatible or incompatible with the pitch. When responses with the same level of compatibility were combined in dual-task conditions, their response codes were congruent to each other, whereas combining a compatible and an incompatible response created mutually incongruent (i.e., conflicting) response codes, potentially inducing detrimental crosstalk. Across age groups, dual-task costs indeed were overall highest with response-code incongruency. In these trials, compatible responses exhibited higher costs than incompatible ones, even after removing trials with strongly synchronized responses. This underadditive cost asymmetry argues against mutual crosstalk as the sole source of interference and corroborates notions of strategic prioritization of limited processing capacity based on mapping-selection difficulty. As expected, the effects of incongruent response codes were found to be especially deleterious in older adults, supporting assumptions of age-related deficits in multiple-action control at the level of task-shielding. Overall, our results suggest that aging is linked to higher response confusability and less efficient flexibility for capacity sharing in dual-task settings.

Brain functional characterization of response-code conflict in dual-tasking and its modulation by age

“…Our behavioral results are a within-scanner replication of our previous findings (Paas Oliveros et al 2023). Consistent with our previous study, our dual-task paradigm elicited response-related conflict by having spatially opposing S-R mapping rules for either hand.…”

“…Alternatively, older adults might suffer from inhibitory deficits affecting the attentional mechanisms for task processing and scheduling attention across different task sets, causing distraction between parallel processing streams (Mayr 2001;Mayr and Liebscher 2001;Hein and Schubert 2004;Paas Oliveros et al 2023). Furthermore, older adults may voluntarily allocate more attentional resources to the more demanding task, leaving the less demanding one largely unattended, possibly explained by an over-reliance on central attention with advanced age (Maquestiaux and Ruthruff 2021).…”

“…The copyright holder for this preprint this version posted March 23, 2023. ; https://doi.org/10.1101/2023.03.21.533669 doi: bioRxiv preprint 2004; Maquestiaux and Ruthruff 2021), or process-specific changes, such as response-code confusability (Paas Oliveros et al 2023).…”

“…However, the specific cognitive and neural mechanisms behind dual-task costs are not fully grasped yet and may be manifold. Previous studies have identified different sources of interference, such as a structural response selection bottleneck (Fagot and Pashler 1992; Pashler 1994), limited parallel processing capacity (Watter and Logan 2006; Miller et al 2009; Koch et al 2018), or crosstalk, which will be the focus of the present study (Pieczykolan and Huestegge 2018; Naefgen et al 2022; Weller et al 2022; Paas Oliveros et al 2023). Crosstalk refers to the non-intentional information transmission between processing streams of different (sub)tasks (Navon and Miller 1987).…”

On doing multi-act arithmetic: A multitrait-multimethod approach of performance dimensions in integrated multitasking

“…For example, in a dual-response paradigm ( Huestegge and Koch, 2013 ; Raettig and Huestegge, 2021 ), the performance registration is directly observable, while in a multi-act (chained) arithmetic paradigm, the units of interest lay hidden and can only indirectly be inferred ( Pieters, 1983 , 1985 ). Since even the simplest decision imposes a considerable demand requiring multiple inhibitory control of alternative response options ( Moeller and Frings, 2019 ; Raettig and Huestegge, 2021 ), it is utterly impossible to reach a definition of multitasking that is minimalistic and universal at the same time ( Ackerman, 1987 ; Logan, 2002 , 2004 ; Altmann and Gray, 2008 ; Kiesel et al, 2010 ; Paas Oliveros et al, 2022 ; Schumann et al, 2022 ).…”