Does teaching students how to explicitly model the causal structure of systems improve their understanding of these systems?

Abstract

If students really understand the systems they study, they would be able to tell how changes in the system would affect a result. This demands that the students understand the mechanisms that drive its behaviour. The study investigates potential merits of learning how to explicitly model the causal structure of systems. The approach and performance of 15 system dynamics students who are taught to explicitly model the causal structure of the systems they study were compared with the approach and performance of 22 engineering students, who generally did not receive such training. The task was to bring a computer-simulated predator-and-prey ecology to equilibrium. The system dynamics students were significantly more likely than the engineering students to correctly frame the problem. They were not much better at solving the task, however. It seemed that they had only learnt how to make models and not how to use them for reasoning.

Keywords:

• engineering education research
• modelling
• external representations
• dynamic systems
• qualitative reasoning

Acknowledgements

This research was supported by the Swedish Armed Forces Research and Development Program. I am indebted to Dr. Erling Moxnes and his colleagues in the System Dynamics Group at the University of Bergen, who allowed me to recruit participants among their students. Dr. Moxnes kindly assisted me in the data collection with the system dynamics students and his laboratory equipment will remain a vivid memory. Amina Henainen recruited the students at the Royal Institute of Technology in Stockholm, and Isabell Andersson recruited participants at Uppsala University. Isabell Andersson served as experimenter with the Uppsala students, and assisted me in collecting data from the engineering students. Finally, I thank Dr. Berndt Brehmer and Dr. James Lyneis for their valuable comments on earlier versions of this paper.

Notes

1. The differential equation is , where x is the displacement from the equilibrium. The solution is , where A is the amplitude, , and ϕ is the phase. This means that . The answer to (a) is 1.6 kN/m and the answer to (b) is 31.2 cm.

Additional information

About the author

Dr Eva Jensen is Senior Lecturer in Command and Control Science at the Swedish National Defence College. She has a Ph.D. in Psychology from Örebro University and an MSc in Electrical Engineering from Chalmers University of Technology. Her field of interest is the support of external representations in system design.