You are a young man, in their 20's. You were a dark blond, blue eyed, white man. Almost a stereotype of a white person. You were pretty tall and a decently athletic build. Girls seemed to find you quite attractive.
The study's main goal was to see what kind of mental or physical issues might arise from suddenly having someone change in their entirety. That's why this experiment was paying so well, they simply had no clue how people might react. Were you going to go mad? Adapt a whole new personality? Be utterly and completely unharmed? They simply had no clue. The end goal, they told you, was for this to be a way to transfer sick people's minds into the bodies of people in vegetative states. Like a whole new level of organ donation. Maybe even use it with two willing subjects that didn't feel at home in their own bodies for one reason or another.
You asked if you were going to have your mind put into someone who was brain dead. But you were not. It was simply not feasible to find enough subjects and besides, your actual body would just wither away if it was to lay in a coma for a year. Another upside to having two people swap with each other was of course the fact you'd have two study subjects for each couple.