The process that best explains the difference in John's attractiveness to women is the one of "relative attractiveness". When John goes out with his friend that is a personal trainer, who is very muscular and fit, John feels like he is less notices by women, than when he goes out with his other friends that are less muscular than the personal trainer. John is comparing his attractiveness with his friends, and how its affected by the company that he has in different moments but at the same scenarios, in this case, in a bar surrounded by women.