Onlooker behaviour (Onl) which was not frequent whatever age group decreased significantly at the end of the preschool years. Children spent also less and less time unoccupied (Uno) with a significant decrease at the beginning and the end of the preschool period. More precisely, interactions with adults (Adu) showed a significant decrease from 2–3 to 4–5 years, becoming rare in the two oldest age groups. A main age effect was found for all the categories. Age effect on the percentages of children's playtime allocation among social play categories ( F and P- values for variances analyses and P-values for Fisher's PLSD post-hoc comparisons among age groups).
Table S2: Developmental trends in social participation over the preschool period.
