0-6 months: children cry in response to another infant"s cries. 6-12 months: child tries to interact with other infants through waving or vocalizing. 25-36 months: child begins to prefer the company of children over adults. 3 years: children begin to prefer same sex playmates. 16-18 years: expects friends to provide emotional support. Toddlers: between the age of 1-2, children make gains in locomotion and language that increase the complexity of their social exchange. During this period they develop the capacity to engage in complementary social interactions: there are 4 types of play that toddlers engage in: Solitary play: children play by themselves and generally ignore other children who are near. About half of 2-year-olds engage in this type of play. Parallel play: two children play in similar activities, often side by side, but do not engage one another. This type of play is common in 2-year-olds but diminished by the time a child is 3 or 4.