title: Social stimulation of vocalizations in delayed infants: familiar and novel agent.
mesh_terms: D001288:Attention; D003216:Conditioning, Operant; D005260:Female; D006801:Humans; D007223:Infant; D008607:Intellectual Disability / Q000523:psychology*; D007804:Language Development; D009034:Mother-Child Relations; D009042:Motivation; D012056:Reinforcement, Social; D012931:Social Environment