Geological time, biological events and the learning transfer problem

Claudia C Johnson, Joan Middendorf, George Rehrey, Mehmet M Dalkilic, Keely Cassidy


Comprehension of geologic time does not come easily, especially for students who are studying the earth sciences for the first time. This project investigated the potential success of two teaching interventions that were designed to help non-science majors enrolled in an introductory geology class gain a richer conceptual understanding of the geologic time scale. Our research centered on the results of those interventions since we hypothesized that students who correctly answered exam questions on relative geologic time early in the semester would be able to respond with equal facility to exam questions at the end of the semester that asked them to apply relative geologic time to associated biologic events.

The instructor of the course began this study by using the Decoding the Disciplines model (Pace & Middendorf, 1998). During the first step of the model, the instructor identified the place where a majority of students in previous classes had the greatest difficulty; that is, in addressing the relative geologic time scale.  Next, the instructor articulated the mental moves an expert geologist makes when solving problems using the geological time scale.  During lecture the instructor modeled those very same mental tasks for students. Students were then given the opportunity to practice those mental tasks by creating their own personal timeline. Later in the course students completed the second intervention, a categorization grid that also functioned as a classroom assessment of their learning. Students were given exams after both interventions were completed.

Results from the first and second interventions indicated that students were able to understand the conceptual framework of the relative geological time scale. On an exam administered after both interventions were completed, 66% of the students answered correctly the questions about relative geologic time, an indication that they had gained conceptual knowledge of the subject. In contrast, only 36% of students answered correctly the exam questions at the end of the semester that focused on relative geologic time with associated biologic events. Pearson Chi-Square tests with P<0.05 were used to test our hypothesis.  Statistically significant results at P=0.00 were attained for all tests, indicating the hypothesis can be rejected.

We conclude that a second, more prevalent, underlying problem exists for non-science majors, one that Thorndike and Woodworth (1901), Byrnes (1996), Bransford, Brown, and Cocking (2000) and Bransford and Schwartz (2001) describe as the learning transfer problem.  Similar problems have been discussed as a knowledge transfer problem (Graham et al., 2006). Learning transfer is problematic for students using the geological time scale and calls for additional classroom interventions – interventions designed and scaffolded to provide students the opportunity to practice the set of difficult mental moves required to apply biological events to the relative geological timeline.


Decoding the Disciplines; learning transfer

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