Optimistic people may contribute to the health of their partners, research finds. The study, with 4,500 heterosexual couples, indicates that having an optimistic partner may stave off the risk factors leading to Alzheimer’s disease, dementia, and cognitive decline as you grow old together. “We spend a lot of time with our partners,” says William Chopik, assistant professor of psychology at Michigan State University and coauthor of the study. “They might encourage us to exercise, eat healthier, or remind us to take our medicine. When your partner is optimistic and healthy, it can translate to similar outcomes in your own life. You actually do experience a rosier future by living longer and staving off cognitive illnesses.” An optimistic partner may encourage eating a salad or work out together to develop healthier lifestyles. For example, if you quit smoking or start exercising, your partner is close to following suit within a few …