Learning theory ; Cognitive psychology ; Wissensdarstellung; Knowledge representation; Representation (mental) ; Natural kind terms; Mental representation ; Mental representation (language acquisition) ; Object individuation; Conceptual development; Konzept (Spracherwerb) ; Concept formation ; Spracherwerb und neurologische Entwicklung; Language acquisition and neurological development; Sprache und Denken (Ontogenese) ; Language and thought (ontogenesis) ; Cognitive development; Language acquisition and cognitive development