Do preschool children use spatial coding for serial order in working memory: a replication study

The ordinal position effect (OPE) refers to the tendency to categorize items from the beginning/end of a memorized sequence with left/right-sided responses, respectively. It is considered as evidence that serial order in WM relies on spatial coding mechanisms. The effect has been well replicated in adults, where it is shown to depend on reading direction. Conversely, so far, only one study (van Dijck, Abrahamse, & Fias, 2020) has assessed the OPE in preliterate children. They found that even though the effect was not significant at the group level, about one third of the children already associated serial order with space, yet with no uniform direction. In the present study, we aimed to replicate these findings in 156 preschool children (mean age: 6.4 years). No systematic spatial coding was observed at the group level. However, individual analysis showed a reliable OPE in 34% of the children. Among those, 58.5% coded from right-to-left while 41.5% were left-to-right mappers. Our findings are thus in line with the results of van Dijck et al. (2020) and support their conclusions that spatial coding of serial order in WM does not depend on the ability to read and write but is likely calibrated by it.