Yeah for me my perceptions of each individual changes when certain aspects of their character change. When the young age is considered we may have a different understanding of behavior. The prefrontal cortex which is the part of the brain that is involved with things like reasoning and impulse control (among many other things), continues to develop in a person until the age of 25. Alex beating Chris may be viewed as a developmental issue, a sign of immaturity and a lack of impulse control due cognitive skills that are not fully developed.
Last Question: How did you perceive each character in terms of gender? Who was male and who was female?
RE: River of Snakes: thought experiment