Operation ARA (Acquiring Research Acumen) is a computerized learning game that teaches critical thinking and scientific reasoning. It is a valuable learning tool that utilizes principles from the science of learning and serious computer games. Students learn the skills of scientific reasoning by engaging in interactive dialogs with avatars. They are tutored by avatars with tutoring sessions that vary depending on how well students have responded to questions about the material they are learning. Students also play a jeopardy-like game against a feisty avatar to identify flaws in research and then generate their own questions to determine the quality of different types of research. The research examples are taken from psychology, biology, and chemistry to help students transfer the thinking skills across domains of knowledge. Early results show encouraging learning gains. (Contains 2 figures and 1 table.)