1992; Ollendick et al., 1992; Wentzel and Asher, 1995), and among those who come into contact with the law (Kupersmidt and Coie, 1990). Whether it is the rejection that causes the later problems or the behaviors that get the child rejected that cause these problems is difficult to disentangle. Both are likely to be true. Importantly, however, not all, nor even most, children who are rejected by other children at some time in their childhood have difficulties of this sort (Parker et al., 1995). In addition, rejected children are not all cut from the same cloth. At least two bases for rejection appear to be important by middle childhood (Cillessen et al., 1992; French, 1988). Some children are rejected because they are mean and aggressive, others because they are shy and withdrawn. The trajectories for these two kinds of rejected children differ. The most is known about rejected aggressive children, who appear to be at risk for all types of externalizing behavioral and emotional problems. Less is known about rejected withdrawn children, although they may be at greater risk for psychiatric problems of the internalizing type (i.e., anxiety, depression) (Hymel et al., 1990; Rubin and Mills, 1988).
Efforts to improve the quality of peer relations have focused largely on school-age children, with few exceptions (Webster-Stratton, 1990). Yet problematic patterns of social interaction can be discerned well before school entry. To facilitate efforts to design appropriate interventions for young children, it is important to understand how their interactions and play with one another change over the early years of life, and why some children negotiate this changing landscape more easily than others.
Views about the development of peer relations have changed over the past half-century or so (Rubin et al., 1998). A report based on what was known in the 1950s would begin by stating that babies really aren't interested in one another, and when they do interact, they treat each other more like objects than like people. It would state that from 24 months onward, while children could have playmates, the development of friendships is beyond their capabilities.
Thousands of hours of observation have modified these views, leading to a much richer appreciation of the interest, capacity, and skills young children bring to their relations with other children, including their friends. Observations have also led to a richer appreciation of the challenges that face children when they try to join into and sustain play with other children of similar age. This increased awareness of the landscape of early peer relations has developed over a period in U.S. society when the amount of time children spend with other unrelated children has increased significantly. For example, as recently as the 1980s, researchers estimated that