For anyone who doubts the value of advocating for greater equality in the world, this video may change your mind. People with annual incomes of less than $35,000 at age 40 don’t live as long as those making $100,000 a year, according to a study published in Science. What’s more, the fewer the social ties, the higher the risk for strokes. And those experiencing a lot of adversity growing up, such as child abuse or malnutrition, die 20 years earlier than those who did not face those challenges, the team concludes. Data from horses, rodents, whales, and nonhuman primates confirm that social factors can be key determinants in health. By merging human and animal studies, the team says, scientists may be better able to figure out how to manage social factors to keep people healthy longer.