Spatialization in working memory is related to literacy and reading direction: Culture "literarily" directs our thoughts.

The ability to maintain arbitrary sequences of items in the mind contributes to major cognitive faculties, such as language, reasoning, and episodic memory. Previous research suggests that serial order working memory is grounded in the brain's spatial attention system. In the present study, we show that the spatially defined mental organization of novel item sequences is related to literacy and varies as a function of reading/writing direction. Specifically, three groups (left-to-right Western readers, right-to-left Arabic readers, and Arabic-speaking illiterates) were asked to memorize random (and non-spatial) sequences of color patches and determine whether a subsequent probe was part of the memorized sequence (e.g., press left key) or not (e.g., press right key). The results showed that Western readers mentally organized the sequences from left to right, Arabic readers spontaneously used the opposite direction, and Arabic-speaking illiterates showed no systematic spatial organization. This finding suggests that cultural conventions shape one of the most "fluid" aspects of human cognition, namely, the spontaneous mental organization of novel non-spatial information.

Can spatialisation be extended to episodic memory and open sets?

The SPoARC effect (Spatial Positional Associated Response Codes) has only been observed in working memory (WM) using closed sets. It is interpreted as showing that individuals spatialise to-be-remembered items in a left-to-right fashion, using spatialisation as context. Given that context is crucial for episodic memory (EM), we tested if this effect could be observed in EM by using 15-word lists taken from an open set. After each list, 30 probes were sequentially displayed to test recognition. The left/right-hand key assignment for yes/no answers was varied. No SPoARC effect was observed. However, as all previous SPoARC experiments had used short lists and closed sets, it was not possible to know if this absence of SPoARC was due to the open set feature or the length of the lists. A second experiment was thus run using open sets and short 5-word lists, which do not necessitate EM to be remembered. A SPoARC effect was observed indicating that Experiment 1 result was due to the involvement of supra-span lists and that SPoARC effects do not extend to EM with open sets. Experiment 2 also enabled us to generalise the SPoARC effect to open sets in WM for the first time.

A SPoARC in the Dark: Spatialization in Verbal Immediate Memory.

In 2011, van Dijck and Fias described a positional SNARC (Spatial-Numerical Association of Response Codes) effect: the SPoARC (Spatial-Positional Association of Response Codes). To-be-remembered items (e.g., numbers, words) presented centrally on a screen seemed to acquire a left-to-right spatial dimension. If confirmed, this spatialization could be crucial for immediate memory theories. However, given the intricate links between visual and spatial dimensions, this effect could be due to the visual presentation (on a computer screen), which could have probed the left-to-right direction of reading/writing. To allow a generalization of this effect, we adapted van Dijck and Fias's (2011) task using an auditory version of Sternberg's paradigm. Lists of five consonants were auditorily presented at a rate of 3 s/item. A SPoARC effect was observed. The consequences are discussed first from an immediate memory perspective, putting forward the view that order could be coded through spatialization, and then in terms of similarities between SPoARC and SNARC.