Caring for the young may delay ageing in the brain. Gro Amdam, who studies ageing in bees at Arizona State University, observed improvements in cognition among older bees that turn their attention back to nursing. This change in social behaviour could help the human brain as well. Amdam’s theory is that when older individuals participate in tasks typically handled by a younger generation – whether in a hive or in our own society – antioxidant levels increase in the brain, which slows the ageing process.