Class inclusion versus quantifiers comprehension tasks: an experimental study with school-aged children.

Literature in developmental psychology pays special attention to the difficulties met by preschool children when confronted with (universal vs. existential) quantified sentences. According to the pivotal Piagetian view, the difficulties exhibited in quantifier comprehension during the preoperational period (age 2-6) derive from the same limitations in logical reasoning that cause bad performance outcomes in class inclusion problems. Nevertheless, as far as we know, a direct comparison between the two tasks has never been produced. In this research we tested the logical hypotheses concerning the failure in quantifier comprehension of preschool children by administering a sentence-picture matching task to two groups of children (5-6 vs. 7-8 years old). Pictures, obtained by partially pairing two entity sets, one of which outnumbers the other, were presented to participants. After each picture, children were asked to answer questions involving quantified versus class inclusion contents. Main findings showed that younger children performed the quantifier task worse than older children and their performance in that task was also worse with respect to the class inclusion task. This difference was not observed with older children who obtained better results than younger children in both tasks. These findings suggest that the specific abilities involved in solving the two problems evolve independently from each other during cognitive development. The results have been discussed in the light of the recent developmental theories.