title: Differential production of positive and negative discriminative stimuli by normal and retarded children.
mesh_terms: D001288:Attention; D002648:Child; D003118:Color Perception; D004193:Discrimination Learning; D005260:Female; D006801:Humans; D008607:Intellectual Disability / Q000523:psychology*; D008297:Male; D011930:Reaction Time; D014040:Token Economy