Summary: The testing effect arises when learners who are tested rather than relearning material obtain superior scores on a final test than those who relearn. Based on cognitive load theory, six experiments examined whether the effect was evident under low or high element interactivity (a measure of complexity) conditions. Students learning to write types of text were participants. In all experiments, effects on a final common test of two presentations were compared with a single presentation followed by a preliminary test. The testing effect on immediate tests was larger and more likely using lower element interactivity materials. A reverse testing effect was likely on immediate tests tapping higher element interactivity material but possibly eliminated by using a delayed test. Copyright © 2017 John Wiley & Sons, Ltd.