Environmental cues can switch longevity pathways on or off, revealing that lifespan is strongly shaped by how organisms sense their surroundings. Credit: Shutterstock Curiosity about extending human life may be especially visible among certain tech enthusiasts today, but people have been fascinated by the idea of a lasting fountain of youth, or even immortality, for thousands of years. Some of the approaches most strongly supported by scientific evidence, such as strict dieting for health and