ABSTRACT
Problem: Researchers wanted to study children's aggressiveness during unstructured free play on school playgrounds. They noted that while children's aggressiveness has been studied in laboratories, where the play activities are often contrived, "children's playground behaviors are markedly understudied even though they have important implications for development." One reason that it is understudied is the difficulty of following children moving freely across the relatively large areas of school playgrounds; even if they can be seen across the playgrounds, it is difficult, if not impossible, to hear what they say.
