Interpreting conjunctions and numerals at three years: evidence for a common logical operation

This study examines the relationship between the conjunction “and” and numerals in children aged 3 to 4 years. Logical terms like “and” are related to expressions with quantifiers, such as numerals. For example, “Cat A and cat B are on the mat” implies “There are two cats on the mat.” Both “and” and numerals can mean “at least two cats” in a basic reading or “exactly two cats” in an enriched interpretation. The psychological link between these interpretations, however, remains largely unexplored.We built on the “Give-n” task, which assesses children’s understanding of numerical expressions, by creating a parallel “Give-and” task to study how children interpret conjunctions, and a control “Give-or” task. By comparing children’s performance across these tasks and analyzing their errors, we found a correlation between their understanding of numbers and “and.” This correlation suggests a common logical operation beyond shallow interpretations.