In order to study the impact of blindness on social and emotional development during the first year of life, the level of social-emotional development was compared in blind and sighted 9- and 12-month-old infants. The five 9-month-old and the 17 12-month-old blind infants were completely blind from birth and exhibited no further serious disabilities. Social-emotional development was assessed with a scale from the Bielefeld Developmental Test for Blind Infants and Preschoolers containing three subscales on emotions, social interaction and impulse control. Compared to non-disabled infants, blind infants exhibited a more limited repertoire of facial expressions and less responsiveness. They less frequently attempted to initiate contact with their mothers (self-initiated interactions) or comply with simple requests and prohibitions than sighted infants. These differences in the social-emotional development of blind and sighted infants are traced back to the effects of blindness on the mother-child interaction. The lack of visual perception appears to impede particularly the acquisition of a dialogue concept.

This empirical study compared the average ages at which four congenitally blind children acquired 29 gross motor skills with age norms for sighted children. The results indicated distinct developmental delays in the acquisition of motor skills and a high degree of variability in developmental delays within and across the six subdomains that were analyzed.

Parents of 85 blind children aged from 10 months to the 6th year of life were asked regarding the frequency, duration and typical situations of the occurrence of various stereotypic behaviors in their children. The Bielefeld Parents' Questionnaire for Blind and Sighted Infants and Preschoolers was used as the instrument of measurement. All of the children displayed at least one stereotypic behavior; most displayed several stereotypic behaviors according to the parents' reports. Eye poking and body rocking dominated within the prevalence hierarchy. Four typical situations could be identified in which stereotypic behaviors were shown: monotony, arousal, demand, and during feeding or eating. The results suggested that repetitive hand and finger movements, stereotypic manipulation of objects, and making a face(s) mainly occur within arousal situations whereas eye poking, whimpering, and sucking thumbs or fingers especially are linked to monotony.

Previous studies have reported that congenitally blind children without any additional impairment reveal a developmental delay of at least 4 years in perspective taking based on testing first-order false-belief tasks. These authors interpret this delay as a sign of autism-like behavior. However, the delay may be caused by testing blind children with false-belief tasks that require visual experience. Therefore, the present study gave alternative false-belief tasks based on tactile or auditory experience to 45 congenitally blind 4-10-year-olds and 37 sighted 3-6-year-olds. Results showed criterion performance at 80 months (6; 8 years) in blind children compared with 61 months (5; 1 years) in sighted controls. It is concluded that this 19-month (1; 7 year) difference, which is comparable with delays in other developmental areas, is a developmental delay caused by the fact of congenital blindness rather than a sign of a psychopathological disorder of autism-like behavior.

This empirical study compared the average ages at which four children with congenital blindness acquired 32 fine motor skills with age norms for sighted children. The results indicated that the children experienced extreme developmental delays in the acquisition of manual skills and a high degree of variability in developmental delays within and across six categories of finemotor skills.