Building the Fundaments for the Future: The Development of Early Communication in the First Two Years of Life

Background: Early communication forms the essential basis from which further cognitive and social development will take place. Major milestones in early communicative development are the emergence of joint attention and language. Joint attention is considered to provide the foundation of shared experience necessary for language acquisition. Early communication skills are commonly found to be impaired in Autism Spectrum Disorders (ASD).

Objectives: To obtain more fine grained information about the development of early communication skills and its individual differences in typical developing children. This may facilitate detecting a deviant pattern of early developmental skills in children with ASD.

Methods: In this current longitudinally study, the absence or presence of joint attention skills like sharing, following and directing attention and language skills were investigated as they emerged between 8 and 24 months of age in a single group of 23 typical developing infants. Data was collected during monthly home visits. First, the age and order of emergence for each specific joint attention skill were calculated. Next, the relation with language through cross-lagged correlations between joint attention skills at each month and the size of comprehensive and productive vocabulary at 8, 12, 18 and 24 months was tested. Last, the implications were investigated of an atypical developmental order of joint attention skills on language development.

Results: All joint attention skills emerged on average between the ages of 8 and 15 months. Based on the mean ages of emergences, the overall order of emergence was: Checking → Sharing attention→ Directing attention → Following attention → Directing attention with gaze alternation (g.a.) → Following attention behind → Referential language. The size of productive vocabulary at 8 months has a positive effect on the presence of directing attention (with g.a.) before the first birthday, but a negative relation in the period when joint attention skills are present in most children. Following attention within the visual field and direction attention with g.a. had an effect on comprehensive language throughout the second year of life. In the total sample, 18 children (78.3%) showed a typical pattern of development, in which checking, sharing, directing and following attention were found to emerge first before the emergence of directing attention with g.a. and following attention behind. The five children with an atypical pattern (with direction attention with g.a. earlier in the developmental sequence) had a larger productive vocabulary at 8 months compared to children with a typical development and an overall tendency to have larger receptive and productive vocabulary until 24 months.

Conclusions: The first two years of life represent a crucially important period in the emergence of early communication skills in which responsive joint attention skills tend to emerge before initiative joint attention. An atypical development does not per se have a negative effect on language, while results indicate that an atypical pattern could improve the size of vocabulary. Though, these children showed a joint attention skill relatively early in development, children with ASD often have a delayed or absent joint attention development, which may result in diminished language skills.