Here we give examples of how insights from psychological research have worked to reduce ill health and optimize well-being of the young generation, how early promotion of cognitive and social skills has put individuals on paths to constructive participation and society, and how psychological preventions can be designed to slow down the decline in cognition and activities in old age. We always demonstrate that science means to help the public and policy makers to distinguish between unwarranted assertions about mind and behavior on the one hand, and reasonable hypotheses and established scientific knowledge on the other. Psychology subscribes to a rigorous methodology to demonstrate causal effects and show evidence of interventions, and to that effect its insights are based on experimental designs, systematic assessments and observations, and longitudinal data. Over time, we will develop a roster of paradigmatic cases for psychology’s proven impact, covering major areas of human functioning and addressing commonalities and differences across cultures.