Research on friendship has established a number of facts, some interesting, some even useful. Did you know that the average student has 5-6 friends, or that a friend who has previously an enemy is liked more than one who has always been on the right side Would you believe that physically attractive individuals are preferred as friends to those less comely, and is it fair that physically attractive defendants are less likely to be found guilty in court Unfortunately, such facts don’t tell us much more about the nature or the purpose of friendship. In fact, studies of friendship seem to implicate more complex factors. For example, one function friendship seems to fulfill is that it supports the image we have of ourselves, and confirms the value of the attitudes we hold. Certainly we appear to project ourselves onto our friends; several studies have shown that we judge them to be more like us than they objectively are. This suggests that we ought to choose friends who are similar to us rather than those who would be complementary. In our experiment, some developing friendships were monitored amongst first-year students living in the same hostel. It was found that similarity of attitudes towards politics, religion and ethics, pastimes and aesthetics was a good prediction of what friendships would be established by the end of four months. There have also been studies of pairings, both voluntary (married couples) or forced (student roommates), to see which remained together and Which split up. Again, the evidence seems to favor similarity as an sign of a successful relationship, though there is an exception: where marriage is concerned, once the field has been narrowed down to potential mates who come from similar backgrounds and share a broad range of attitudes and values, a degree of complementarity (互补) seems to become desirable. Similarity can breed contempt; it has also been found that when we find others offensive, we dislike them more if they are like us than when they are dissimilar. The difficulty of linking friendship with similarity of personality probably reflects the complexity of our personalities: we have many sides and therefore require a different group of friends to support us. This of course can explain why we may have two close friends who have little in common, and indeed dislike each other. By and large, though, it looks as though we would do well to choose friends (and spouses) who resemble us. If this were not so, computer dating agencies would have gone out of business years ago. What do studies of marriage relationship indicate

A happy marriage must be based on the completely same likes and dislikes.
B. It can only be successful when the couple share the same attitudes and values.
C. The only difference between marriage and friendship is that the former is voluntary.
D. The most successful are between people who are alike but not exactly the same.