This research study investigated the learning outcomes of a brief systems thinking intervention at the undergraduate level. A pre/post experimental design (n = 50) was used to address two primary questions: (1) Can a brief introduction to systems thinking improve students' understanding of systems thinking? and (2) Which teaching method (of two) works best under such time constraints? Participants were divided into three groups: control, lecture only, and model demonstration. Test results suggest that both lecture-only and model-manipulation groups increased their understanding of systems thinking slightly over the control group, but showed no significant difference between each other. Results from focus groups conducted 3 months after the intervention suggest that model-manipulation participants may have been more successful than lecture-only participants at incorporating systems thinking into their own mental models to understand an ecological system.