Classroom dialogues have special educational value because they allow students to engage critically but constructively with each other’s ideas, solve scientific problems jointly and develop their scientific understanding. The present study focuses on how groups of twelfth-grade high school and university students communicate and co-operate through dialogue to solve a biological problem they have not encountered before. The specific research questions are as follows: (a) What are the dialogic structures that help students construct scientific explanations? (b) How does prior scientific knowledge support student dialogue in constructing explanations? A coding scheme was developed inductively for the analysis of participants’ utterances. We use illustrative exemplars from participants’ dialogues to discuss those aspects which might support explanatory reasoning. We focus on reasoned attention for contending opinions and striving for consensus that characterise cases of constructive dialogue. We also discuss observed objections and disagreements as triggering factors for constructive alternative explanations. Finally, we discuss the evidence showing that while prior knowledge supports student reasoning it can also hinder the ability of students to think in a creative way.

课堂对话具有特殊的教育价值，因为它们使学生能够批判性地，建设性地彼此交流想法，共同解决科学问题并发展他们的科学理解。本研究的重点是十二年级高中和大学生群体如何通过对话进行交流和合作，以解决他们以前从未遇到过的生物学问题。具体的研究问题如下：（a）帮助学生构建科学解释的对话结构是什么？（b）先前的科学知识如何在构建解释时支持学生对话？归纳地开发了一种编码方案，用于分析参与者的话语。我们使用参与者对话中的示例性范例来讨论那些可能支持解释性推理的方面。我们将注意力集中在主张建设性对话的典型观点上，即争夺观点和争取达成共识。我们还将讨论观察到的异议和分歧，将其作为建设性替代解释的触发因素。最后，我们讨论的证据表明，先验知识虽然支持学生推理，但也会阻碍学生以创新方式思考的能力。