Can spatialisation be extended to episodic memory and open sets?

ABSTRACT

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.

KEYWORDS:

• Episodic memory
• working memory
• SPoARC
• ordinal position effect
• open set

Acknowledgments

We would like to thank Jacqueline Guida for her comments and helping us to edit and proofread this article.

Disclosure statement

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Notes

1 We use the term WM also to include short-term memory.

2 Lewandowsky and Farrell (2008, p. 41) wrote: “The use of context markers [tags] does, however, entail a cost: As in many other models (e.g., SEM; Henson, 1998), the structure of the markers across positions is assumed rather than explained by the model”.

3 More specifically, in case a positive effect is detected in Experiment 2, it would mean that the first experiment was negative because of the supra-span length or because of the supra-span length and the open set.

4 An explanation for this lack of result could come from inter-individual differences in terms of WM-size and chunking strategies, these could have made the several WM-size SPoARC(s) more difficult to be inferentially observed as their size would vary among (and maybe within) individuals. The same variability would be less impacting in Experiment 2 as the size of the SPoARC was imposed by the experimental conditions, that is, five elements to be remembered.

5 It is to be noted that in the SNARC domain, a slope around six or seven (or even inferior) is not unusual (e.g., Dehaene et al., 1993; Fias et al., 1996; Gevers et al., 2003; Ito & Hatta, 2004; Nuerk, Wood, & Willmes, 2005).