Introduction

Ethnographic studies of social interaction and everyday cognition amply demonstrate that children are capable of complex and abstract reasoning in their everyday, out-of-school activities (Bloome & Horowitz, 1991; Cook-Gumperz, 1986; Goodwin, 1990; Heath, 1983; Rogoff & Lave, 1984; Saxe, 1988). But how do children come to take on the particular roles and discourse forms that are valued in problem posing and problem solving in school? Although children do bring their out-of-school reasoning abilities into the classroom, this thinking is often not taken up and developed as part of the classroom work unless children can display it in ways that teachers recognize (Michaels, O'Connor, & Richards, 1993).

How do students come to appropriate and publicly communicate with the forms of talk or text that are part of being a competent hypothesizes evidence provider, maker of distinctions, checker of facts? For some children these discursive practices never become natural, yet for others they seem to fit from the first day of school. Research suggests that language socialization patterns in the home provide a basis for some of these roles and actions (Heath, 1983; Ochs, Taylor, Rudolph, & Smith, 1991).