title: Experimental inductions of the conservation of "first-order" quantitative invariants.
mesh_terms: D002648:Child; D002657:Child Development; D003210:Concept Formation; D003213:Conditioning, Psychological; D005108:Extinction, Psychological; D006801:Humans; D007858:Learning; D012858:Size Perception; D014163:Transfer, Psychology; D014892:Weight Perception