Out of curiosity, Tyger McSwain is conducting an applied research to see if people are born to with genes that make them skinny or overweight. Tyger McSwain is a developmental psychologists who studies how and why human beings change over the course of their life. Many people think they are born with genes to makes their body structure a certain way and can cause a nature/nurture Debate with many professions. This research uses the behavior genetics perspective since it looks at the role of genetic and environmental influences in human behavior. This research uses the theory of functionalism instead of structuralism because we look at the adaptiveness of the mental or behavioral