If you felt misty-eyed in watching those shots, you were probably experiencing a very healthy dose of empathy. Speaking of prosocial behavior, there was Roger's self-sacrifice for Elisabeth. Roger had no such gain waiting for him, other than a re-affirmation of his feelings of affection for Elisabeth. Social psychologists distinguish between altruism and egoism in the motivation to act prosocially. Altruism is acting good without personal gain whereas egoism is acting in way that best serves your own interests.
Some theorists argue that there are very few instances of truly altruistic act.
Indeed, you could argue that Roger was going to be kicked off the next week and this was his chance to exit gracefully, even as a hero. I would prefer to be more hopeful and think that Roger really was acting altruistically - and setting a wonderful example. One definite goal is social perception is accuracy. If you can accurate judge other people, you can more easily navigate the social world. So far, all the viewers have been trying to accurately judge the survivors, but the question of accuracy should definitely on everyone's mind.