Shape and spatial working memory capacities are mostly independent

Abstract

Whether visual working memory (WM) consists of a common storage resource or of multiple subsystems has been a controversial issue. Logie (1995) suggested that it can be divided into visual (for color, shape, objects, etc.) and spatial WM (for location). However, a recent study reported evidence against this hypothesis. Using a dual task paradigm, Wood (2011) showed interference between shape and spatial WM capacities, suggesting that they share a common resource limitation. We re-examined this finding controlling possible confounding factors, including the way to present spatial location cues, task order, and type of WM load to be manipulated. The same pattern of results was successfully reproduced, but only in a highly powered experiment (N = 90), and therefore the size of interference was estimated to be quite small (d = 0.24). Thus, these data offer a way to reconcile seemingly contradicting previous findings. On the one hand, some part of the storage system is genuinely shared by shape and spatial WM systems, confirming the report of Wood (2011). On the other hand, the amount of the overlap is only minimal, and therefore the two systems should be regarded as mostly independent from each other, supporting the classical visuo-spatial separation hypothesis.

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

“…A dual-task paradigm is often used to examine the interaction between two distinct mental mechanisms, such as the interaction between attention and WM (e.g., Woodman et al, 2001; Xin & Li, 2020), and the interaction between spatial WM and visual WM (e.g., Sanada et al, 2015; Wood, 2011). However, because attention is involved in the maintenance of WM (Barrouillet et al, 2011; Cowan, 2005), when dual-task cost in capacity is observed in a WM task it is often difficult to tell whether the dual-task cost is due to interference from executive processes or from nonexecutive processes (such as interference across WM representations).…”

“…This issue affects at least two types of studies when using the dual-task paradigm. One is to study whether different stimuli (e.g., spatial vs. visual) depend on a common representation substrate (Sanada et al, 2015; Wood, 2011). The other is to explore whether information presented in a nonmemory task (e.g., target detection) is stored in WM (Oberauer & Kliegl, 2006; Oberauer et al, 2012).…”

Individual differences reveal limited mixed-category effects during a visual working memory task

“…In other words, mixed-category trials spread the WM load across a larger pool of neurons compared to uniform-category trials. Our inspiration was to follow up on work demonstrating a mixed-category benefit in a large group of behavioral participants and associating it with more distinct neural patterns in a separate, smaller group of fMRI participants (Cohen et al, 2014), and work revealing detectible classification differences in category-selective regions during WM tasks (Han et al, 2013; Johnson & Johnson, 2014; Sanada et al, 2015). What we observed was more complex and nuanced, as is often the case.…”

“…It follows that WM trials distributing neural activity across different category-specific regions might support WM performance better than when the stimuli fall within the same category. Support for this view comes from a recent paper showing little interference in WM when the stimuli were visual shapes and visuospatial stimuli believed to have distinct neural representations (Sanada, Ikeda, & Hasegawa, 2015).…”

Adaptive multi-modal interface model concerning mental workload in take-over request during semi-autonomous driving

“…Based on the multicomponent workspace of working memory in working memory theory [12], working memory has temporary limited-capacity memory systems for verbal (articulatory loop) and non-verbal (visuospatial scratchpad) material that connects with the content from long-term memory. However, according to the research conducted by Sanada [13] in 2015, shape and spatial workingmemory capacities are mostly independent. Therefore, we needed to test whether visual and spatial channels in the cognition stage should be separated as well.…”