Eight severely retarded subjects (ages 9-22), four with functional language and four without, performed identity and nonidentity matching tasks employing objects, photographs, and line drawings. As representational complexity increased, greater difficulty in matching stimuli was observed in the nonfunctional language group, with line drawings…

Play behaviors of infants who had normal hearing or were deaf were observed during free play with their mothers, at ages 9, 12, and 18 months. Participants included 15 dyads of children who were deaf and mothers who were not, 15 dyads of children and mothers who were both deaf, and 15 dyads of children and mothers who both had normal hearing.…