How do children and adults interpret a false conditional statement, such as “It is false that if it is a triangle, then it has not 4 sides”? While previous research has documented that adults often apply a small-scope negation strategy—reformulating such statements as “If it is a triangle, then it does not have 4 sides”—it remains unknown whether school-aged children use similar strategies. This study explores developmental differences in the comprehension of false conditionals, using contexts that are transferable to educational settings. We presented more than 200 adults and children with conditionals embedded in everyday scenarios (e.g., “It is false that if María went to the party, she carried a purse”) and asked them to generate logically equivalent statements. Adults predominantly used conditional reformulations with a negated consequent (“If A, then not B”), whereas children more often relied on case-based reasoning, describing specific possibilities (“not A and not B”). These results underscore important differences in how false conditionals are processed across age groups and suggest that the use of negated conditionals may be pedagogically problematic for younger learners. The findings offer guidance for educators aiming to understand the development of logical reasoning skills during childhood.

Keywords: Development, deduction, false conditionals.