In this study done on rhesus monkeys, female monkeys were slowly introduced to each other to form a group of five female monkeys. The point of introducing them one after another was to play to their concept of seniority. The monkeys earliest in the group were considered socially superior to the ones introduced to the group later. After a year, they mixed up the members and reintroduced them so they would have different rankings. Blood was drawn from the first and second round of groups to compare how they are affected by bacterial and viral disease. The data showed that more than 5,000 genes were expressed differently in the blood collected from the second round fighting off a bacterial infection, and almost 3,000 genes were expressed differently from viral infection. Both of these changes are a result of social ranks the monkeys first had, to the change in behaviour when their rank shifted. It shows conclusively that past experiences do impact how we respond to our world, even as an adult.
original link: https://www.medicalnewstoday.com/articles/326755.php#6
related link: http://primate.uchicago.edu/2011CayoBook02.pdf