Dual-task costs in memory recall precision reflect shared representational space.

Abstract

A dual-task paradigm is widely used to explore the interaction between two distinct mental mechanisms. However, the effectiveness of a dual-task paradigm is greatly reduced when studying working memory, because it is hard to distinguish dual-task interference due to shared executive processes from that due to shared memory storage. In the present study, we provided convergent evidence that dual-task cost in recall precision is a specific indicator of evaluating the interference across working memory representations that is irrelevant to executive processing. Experiments 1 and 2 showed that when two working memory tasks were performed concurrently, dual-task cost in recall precision showed up only if stimuli in the two tasks shared overlapping representational space. Experiments 3 and 4 found that when a working memory task was conducted concurrently with an attention-consuming task, no dual-task cost in recall precision showed up as long as stimuli in the two tasks did not share overlapping representational space. Experiment 5 further revealed that if a single-object tracking task is conducted while holding both color and location information in working memory, the tracking task would specifically affect the recall precision of the retrieved location (but not of the retrieved color). The present results suggested that dual-task cost in recall precision may provide a convenient and specific index for evaluating interference across working memory storage.

When learning hurts control: inducing cross-task-covariance causes multitasking costs

“…Schacherer and Hazeltine (2021) recently found in a dual-task study with visual and auditory stimulus and response modalities that dual-task costs were larger when the relationship between the stimuli and action effects (e.g., a sound played after a key press response to a visual stimulus) had high conceptual overlap between tasks rather than within tasks (e.g., picture of a pig for one stimulus and an oink sound for a different stimulus vs. a picture of a pig and an oink sound for the same stimulus). Similarly, Li and Li (2021) observed in a combined dual-task visual working memory and multiple-object tracking study that recall precision in the memory task was only impaired when the tasks shared overlapping modalities (i.e., both tapping spatial judgements as opposed to tapping spatial and identity judgments). Collectively both these results fit nicely within our framework, where it is shared representational variance between tasks that drives multitasking costs.…”