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21st Century Research and Development Center on Cognition and Science Instruction

The research reported here was supported by the Institute of Education Sciences, U.S. Department of Education, through Grant R305C080009 to the University of Illinois, Urbana-Champaign. The opinions expressed are those of the authors and do not represent views of the Institute or the U.S. Department of Education.

F. Joseph Merlino, PI



Jennifer Cromley

Nora Newcombe

Christian Schunn

Timothy Nokes 

Andy Porter

Christine Massey 

Keith Kershner



Donna Cleland

Gary Cooper

Deanna Daugherty

Nancy Burns

The center, known as 21 PSTEM, has modified 6 units from middle school science curriculum and has conducted a randomized controlled field trial of these modifications. Using two different curricula, we compared scores for control (usual instruction), limited treatment (teachers received content-based professional development only), and full treatment (teachers received both content and pedagogical [modifications-based] professional development). Each year, more than 300 schools serving 30,000 students in 6th through 8th grade science classes from Pennsylvania and Arizona were in the study.

Curriculum modifications made to the two curricula follow three key principles from cognitive science: diagrammatic reasoning, contrasting cases/analogical reasoning, and background knowledge/misconceptions.

We modified both textbook (written) materials and classroom activities and provided teacher professional development on these modified materials in order to increase students’ learning of both scientific information and scientific reasoning. First, to build analogical reasoning, we developed contrasting case instructional materials and exercises based on the work of Bransford and Schwartz (1998). For example, students’ understanding of concepts related to evaporation in the Holt and FOSS cell biology units were improved by asking students to read about and reason with the contrast between dominant and recessive traits.

Second, to improve students’ diagrammatic reasoning, we identified specific difficulties (e.g., Hegarty, Kriz, & Cate, 2003) that students have with visual representations in the Holt and FOSS materials. For example, the line diagram depicting the water cycle in the Holt textbook includes text, a caption and arrows depicting a dynamic cyclical system. Students may fail to use, understand, and/or coordinate each of these features, and we have provided direct instruction and scaffolded practice for using existing diagrams.


Third, students bring limited amounts of background knowledge and often specific misconceptions about the natural world to their learning of these science topics. To continue with our example from the water cycle, students have misconceptions about evaporation (that it is visible, only happens from large bodies of water, etc.), condensation, and other scientific phenomena (Henriquez, 2005). With regard to teacher professional development, teachers needed a better understanding of these phenomena themselves (content knowledge) as well as an understanding of difficulties for students in learning these skills (pedagogical knowledge) as applied to these specific content areas (pedagogical content knowledge; Shulman, 2000).

We tested during the 2009-2010 through 2012-2013 school years whether these text, activity, and professional development modifications result in higher performance on standardized science measures because teachers successfully help students develop better scientific reasoning skills and more scientific knowledge to apply these skills to. Effects on student learning have been measured with state standardized high-stakes tests, unit-specific researcher-developed measure constructed from released NAEP items, and diagrammatic and analogical reasoning-specific items.

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