title: Structural models and embedded-figure difficulty for normal and retarded children.
mesh_terms: D000293:Adolescent; D002648:Child; D002657:Child Development; D005260:Female; D005556:Form Perception; D006801:Humans; D008607:Intellectual Disability; D008297:Male; D008960:Models, Psychological; D011581:Psychological Tests; D013647:Task Performance and Analysis; D013997:Time Factors