Imagine you do something you feel horribly about to someone else, and then imagine a time you helped someone. How will each action impact how much you like or hate that person?
Folk wisdom would suggest that harming someone, if we feel bad about it, should perhaps make us like the person we harmed more. And, further, that we often don't like people who ask for our help. Such requests invonvenience us, especially if the request is large or we don't know the person. However, several lines of research suggest that helping elicits greater liking for people we help and that harming others elicits greater dislike for people we harm.
1) Cognitive Dissonance: Cognitive dissonance research has demonstrated that when there is a conflict between who we think we are (e.g., "I am a good person") and our behavior (e.g., I hurt that person's feelings), this elicits psychological discomfort, which people must resolve. For instance, research shows that when participants are asked to help an experimenter, they like that person more than if they are not asked to help him or her. The basic idea is that people think "I did a nice thing for him/her, so I must like him/her." If people didn't like the experimenter, then there would be dissonance between their behavior and their attitudes, which people are motivated to avoid.
Conversely, when we harm someone, the view of ourselves as good people conflicts with our hurtful behavior. One quick way to alleviate dissonance is to blame the person or group we have harmed. This makes our hurtful action ok in our own minds, because the other person deserved it or is otherwise evil, immoral or whatever else (so the action isn't so evil. The other person had it coming).
2) Killing begets killing: Research by Andy Martens (professor at The University of Auckland) has found that people feel les discomfort when killing things, the more they kill them. In these studies, people tend to feel progressively better killing a bug, with each bug they kill. In other words, the first bug is harder to kill emotionally than the fifth bug, and the tenth bug is easier than the fifth bug. Now, there obviously are a lot of differences between killing a human and a bug, but this does suggest that when we harm something, we tend to have less regard for it. This parellels other work showing that we have less moral concern for cows after eating meat, and the majority of reports from soldiers who say that killing is next to impossible at first, but (though still terrible) gets easier with time.
3) Hiding Moral Hypocrisy: A study recently published in the Personality and Social Psychology Bulletin (by Lisa Shu and colleagues of Harvard University) tested how people justify their immoral actions to themselves. This research found that when people do something they think is immoral (like cheating, or stealing) they later are less likely to remember an honor code they had previously read. Further, they were more likely to morally disengage, such as by thinking that cheating is more ok and that rules are flexible. In other words, when people do a harmful act, they tend to adjust the rules to justify their own immorality.
Although not directly tested in these studies, this probably suggests that when people harm someone else, they do not tend to think more favorably of the person. Rather, because they would want to morally justify to themselves why they harmed the person, they would be likely come to dislike the person they harmed (it is easier to feel ok about harming someone if we don't value them). This is roughly consistent with what Albert Bandura's (a psychologist at Stanford University) work has found; for instance, people who are most likely to support a war, are also most likely to dehumanize soldiers on the opposite side of a conflict (which clearly have been harmed).
The next time you find yourself hating someone, or you want to like someone more, help them more and harm them less. In time, you will find that you have a greater liking for more and more people. And, as the norm of reciprocity pretty much dictates, they will probably be more likely to like you in return.
After all, as my undergraduate psychology advisor used to quip, "how can I not like someone who has the fine tastes to like me?"
