Abstract
The authors examined the types of discourse structures that emerge during peer learning and the ways in which those structures are related to learning. One hundred and five 5th graders learned about writing conclusions that summarized the results of experiments they had conducted with electrical circuits. In groups of 4, they discussed the quality of 3 conclusions. The discourse structure of the discussions could be readily characterized as a network of arguments and counterarguments. The quantitative measures of the quality of those argument structures were positively related to improvement in the students' ability to write their own conclusions. In addition, the students who simply discussed whether the 3 conclusions were OK or not OK generated less complex argument structures than the students who discussed which of the 3 conclusions was best and which was worst. The results demonstrate the importance of considering the structure of peer discourse as a mediator of what students learn from peer interactions.