People can represent quantities in different ways. Numbers can be represented non-symbolically through an Object Tracking System (for small quantities, when one immediately perceives how many objects are there) and an Approximate Number System (for large quantities), and symbolically, for example with Arabic symbols or words. One unresolved question is the extent to which using these numerical representations, and transferring between them, can be done automatically, or rather involves components of working memory. Key relevant working memory components are the phonological loop and the visuospatial sketchpad.
 
In this study, Xenidou-Dervou and colleagues (2025) asked subjects to perform a dot comparison task with small and large numbers, to engage the non-symbolic systems, and a digit comparison task, to engage the symbolic system, and a cross modal task to engage translation between the systems. Participants either performed these tasks alone or with a secondary task, one that loaded either the phonological loop or else the visuospatial sketchpad. In the comparison of symbolic numerals, the visual secondary task itself was performed more poorly in dual rather than single task conditions, indicating the involvement of the visual spatial sketchpad in use of symbolic numerals. The visual secondary task interfered with non-symbolic number judgements, indicating involvement of the visuospatial sketch pad with the non-symbolic system as well. Finally, the translation between the systems also involved the visuospatial sketchpad, as shown by the secondary task itself suffering dual task interference. In sum, there was evidence for the visuospatial sketchpad, but not for the phonological loop, playing a role in simple comparisons using either or both of the symbolic and non-symbolic number systems. 

The Stage 2 manuscript was evaluated over two rounds of in-depth review. Based on detailed responses to the reviewers’ comments and edits to the Stage 2 report, the recommender judged that the manuscript met the Stage 2 criteria for recommendation.
 
URL to the preregistered Stage 1 protocol: https://osf.io/32qdw
 
Level of bias control achieved: Level 6. No part of the data or evidence that was used to answer the research question was generated until after IPA.
 
List of eligible PCI RR-friendly journals:

 

 

 

Xenidou-Dervou, I., Appleton, C., Rossi, S., Guy, N., & Gilmore, C. (2025). Can adults automatically process and translate between numerical representations? [Stage 2]. Acceptance of Version 3 by Peer Community in Registered Reports. https://osf.io/me6tn