A foreign professor recently pointed out that a person with a baby face means he will enjoy a longer life, because people's living conditions are easily reflected in their faces  Since the spring of 1990, the professor's team has conducted physical and cognitive tests on 1826 pairs of twins over the age of 70 and took pictures of their faces  Without knowing their exact age, three research assistants first assessed the age of twins in different age groups and found that even twins were very different in age  The team then followed the twins' lives in their later years for several years until they died
If the survey is extended to twins over the age of 40, the results may be different
 The older the twins, the more likely they are to die first, according to the survey