This study tested the hypothesis that Soviet day care children (aged 16 to 38 months) derive emotional support from the presence of their group-mates. Children were observed in a strange situation in one of three conditions: with a familiar peer (a group-mate), with an unfamiliar peer (a child from another group), or alone (without a peer). An adult stranger was present during two of the three 4-minute episodes. Results indicated that children with familiar peers were more comfortable than children with unfamiliar peers who, in turn, were more comfortable than children who were alone. Children paired with unfamiliar peers, but not children paired with familiar peers, were upset by the departure of the adult stranger. Alone condition subjects were more upset than other subjects whether the adult stranger was present or absent. Children with familiar or unfamiliar peers made more attempts to catch the adult stranger's attention than each other's. Overt approaches were equally infrequent to familiar and unfamiliar peers. Nonetheless, partners' reactions to the strange situation were reliably similar, indicating that there was behavioral contagion. Girls were somewhat less distressed than boys. For both sexes, age was negatively correlated with the degree of distress. (Author/JMB)