Executive functioning in the first 24 months: A scoping review of the A-not-B task

Recent studies highlight the importance of early executive functioning (EF); notwithstanding, these studies remain limited due to methodological difficulties. The A-not-B task has been adapted to assess EF; however, variations in its administration hinder result comparability and standardization. This scoping review mapped the procedures used in studies employing the A-not-B task to assess EF in children up to 24 months. Searches were conducted in PubMed, Scopus, and Web of Science for empirical studies published in English. From 350 references, 53 articles were included. Most studies primarily focused on assessing global EF, working memory, and inhibitory control; employed the standard two-locations task with fixed delays, used two consecutive correct trials to switch locations, and measured accuracy as the main outcome. Testing typically ended after the completion of trials/sequences. Few studies reported inclusion criteria. This review summarizes A-not-B procedures to identify research gaps and support methodological consistency in early EF assessment.