What children and adults understand when a conditional is said to be false

What does it mean to say that if something is a triangle, then it does not have 4 sides? While adults typically conclude with a new conditional featuring a negated consequent - "If it is a triangle, then it does not have 4 sides" - using a small-scope strategy, no studies have tested whether children do the same. This study examines how children and adults interpret the falsity of conditional statements. Participants evaluated conditionals with everyday content, such as "It is false that if María went to the party, she carried a purse." Drawing on deductive theories, we tested their ability to draw conclusions from false conditionals and to complete conditional and conjunctive sentence structures. Sixty-eight adults and 178 children (ages 8-12) completed two tasks: (1) generating conclusions from true and false conditionals and (2) completing conditional structures with missing elements. Adults mainly reformulated false conditionals into new ones (e.g., "If María went to the party, she did not carry a purse"), while children tended to adopt case-based interpretations (e.g., "she did not go and did not carry a purse"). When completing sentence structures, adults relied more on small-scope strategies (affirming antecedents and negating consequents), while children's responses were more varied and less systematic. Adults judged conditionals to be at least partially indeterminate in about half the cases; children did so rarely. These findings reveal developmental differences in interpreting false conditionals and suggest caution in using negated conditionals with children, who do not process them as adults do.