Studying Students' Mechanistic Explanations across Undergraduate Chemistry and Biology Courses

许多STEM学生在将思想和推理从一个班级转移到另一个班级方面存在困难，例如，将入门课程中学到的知识转移到更高级的班级，或者跨学科。这个项目将考察本科生如何在三个领域的入门课程中使用核心思想和机械解释：化学，细胞和分子生物学，以及生物生物学。这项研究将仔细评估学生在接下来的课程中如何使用他们在必修课中学到的知识，以及这与推理和理解的发展是如何联系起来的。特别是，学生们将被要求生成解释他们正在研究的问题的模型，例如为什么一个患者可以用抗生素治愈，而另一个患者不能。开发包括事情如何发生以及为什么发生的机制和模型的解释是学生需要掌握的一项重要技能，这将有助于他们进入科学或专业工作大军。对这些解释的分析将提供关于以下方面的有价值的信息：1)学生如何将思想从化学应用到生物，以及2)帮助学生获得使用机制和模型开发高质量解释的技能的因素。这些信息将导致改进的教学，使学生在科学入门课程之间最大限度地应用思想，并支持学生毕业和开始职业生涯后所需的推理技能的发展。这个项目将利用一个独特的机会，让来自四个系的研究人员探索学生掌握学科思想和开发机械解释的技能对他们跨课程联系核心思想的能力的影响。该项目将对学生在三门连续的入门课程：化学、细胞和分子生物学以及有机体生物学中的机械解释进行横截面、比较分析。在每门课程中，学生将使用图表和写作相结合的方式来解释如何以及为什么会发生一系列三个相关的现象。这些机械论解释将分析潜在因素之间的因果关系，为现象提供科学合理的解释所需。这些分析将决定：1)本科生STEM课程的学生是否使用相关的核心学科概念来解释现象的发生方式和原因；2)解释的复杂程度在课程中的不同点有何不同；3)一门学科的机械式解释复杂程度对使用相关学科的核心概念解释其他学科的现象的影响；以及4)人口统计学变量和学术变量、解释复杂程度和课程考试成绩之间的关系。这项研究的结果将推动对学生的学科核心思想和解释实践的性质和联系的研究，超越单一课程，通过查看课程。本研究中使用的评估工具和分析技术将为这一未被研究的领域的进一步研究提供基础，包括未来的纵向研究和关于教学对学生构建复杂解释能力的影响的研究。这项工作的见解也将被用来开发一个以证据为基础的教学框架。该框架将提供化学和生物入门课程的学习目标的进展情况，说明每门课程需要掌握哪些内容，以便在后续课程中作出复杂的解释。此外，该框架将记录学生使用词汇在课程之间建立联系的常见方式，以及不同课程之间的词汇差异如何阻止课程之间的思想转移。这一框架将成为未来以证据为基础的STEM课程和课程重塑努力的指南，旨在培养准备充分的公民和科学家。

Many STEM students have difficulty in transferring ideas and reasoning from one class to another, for example in transferring knowledge gained in introductory classes into more advanced classes, or across disciplines. This project will examine how undergraduate students use core ideas and mechanistic explanations across introductory courses in three areas: chemistry, cell and molecular biology, and organismal biology. This study will carefully evaluate how students are using what they have learned in a prerequisite course when they take subsequent courses and how this connects with the development of reasoning and understanding. In particular, students will be asked to generate models that explain the problems that they are studying, such as why one patient is cured by an antibiotic while another patient is not. Developing explanations that include mechanisms and models of how and why things happen is an important skill for students to master, and will help them as they enter the scientific or professional workforce. Analysis of these explanations will provide valuable information about: 1) how students apply ideas from chemistry to biology, and 2) factors that help students gain skills in developing high-quality explanations using mechanisms and models. This information will lead to improved teaching that maximizes student application of ideas between introductory science courses and supports the development of reasoning skills needed after students graduate and begin their careers. This project will take advantage of a unique opportunity for researchers from four departments to explore the impact of students' mastery of disciplinary ideas and skills at developing mechanistic explanations on their ability to connect core ideas across courses. The project will use a cross-sectional, comparative analysis of students' mechanistic explanations within and across three sequential introductory courses: chemistry, cell and molecular biology, and organismal biology. In each course, students will use a combination of diagrams and writing to explain how and why a series of three related phenomena occur. The mechanistic explanations will be analyzed for cause-and-effect relationships between underlying factors needed to provide a scientifically sound explanation of the phenomena. These analyses will determine: 1) if students in undergraduate STEM courses use relevant core disciplinary ideas to explain how and why phenomena occur; 2) how explanation sophistication varies at different points in the curriculum; 3) the impact of mechanistic explanation sophistication in one discipline on the use of related disciplinary core ideas to explain phenomena in other disciplines; and 4) relationships between demographic and academic variables, explanation sophistication, and success on course exams. Findings from this study will advance research on the nature of and connections between students' disciplinary core ideas and explanatory practices beyond single courses by looking across courses. The assessment tools and analysis techniques used in this study will provide a foundation for further research in this understudied area including future longitudinal studies and research on the impact of instruction on students' abilities to construct sophisticated explanations. Insights from this work will also be used to develop an evidence-based instruction framework. The framework will provide a progression of learning objectives across introductory chemistry and biology courses indicating what needs to be mastered in each course to produce sophisticated explanations in subsequent courses. In addition, the framework will document common ways students use vocabulary to make connections between the courses as well as ways how differences in vocabulary between courses prevents transfer of ideas across courses. This framework will serve as a guide for future evidence-based STEM course and curriculum remodeling efforts geared toward producing well-prepared citizens and scientists.