The scientific mission of the Max Planck Research Group for Rationality Enhancement is to lay the cognitive and technological foundations for helping people become more effective. Our two-pronged approach synergistically combines basic research on the computational mechanisms of human learning and decision-making with the development of intelligent systems for enhancing human rationality. Our basic research focuses on how people learn how to decide, decision strategies that make optimal use of limited time and bounded cognitive resources, cognitive control, planning, and goal-setting. Our applied research translates the resulting theories and computational models into cognitive tutors that teach people how to make better decisions and cognitive prostheses that augment people's limited cognitive capacities with artificial intelligence. We evaluate the models, cognitive tutors, and cognitive prostheses we develop in experiments conducted online, in the lab, and in the field. Ultimately, we aim to produce technologies that enhance human productivity, accelerate personal development, and assist people in goal setting and goal achievement.