Social psychologists are used to hearing that their experiments are a waste of time because they just prove the obvious, and tell us what we always knew. But there is a very simple and effective riposte to this accusation. The trouble with folk wisdom (what we always knew) is that it tends to come in pairs of statements, both of which are `obviously' true, but which unfortunately are mutually exclusive. For example, we all know that too many cooks spoil the broth. But wait a minute: don't many hands make light work.
There is one other preconception to be removed before tackling the question of whom we like and love, whom we find attractive and make friends with. Why bother to study an area in which we are all expert practitioners? Surely we can all make friends and organise social relationships naturally, without any assistance from behavioural scientists? Well, if you believe that, have a word with a marriage guidance counsellor, a psychiatrist, or someone involved in industrial relations.
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 was 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 titbits don't tell us much more about the nature or the purpose of friendship.
Why do we make friends? Students of animal behaviour have pointed out that social attraction has an obvious adaptive function: it helps a species both to protect and to reproduce itself. Behaviourists have postulated an affiliation drive, similar to the more familiar drives of hunger, thirst or sex. But although afilliative behaviour shares some of the properties associated with biological drives, I doubt whether our desire to make friends is really much influenced by adaptive considerations.
In fact, studies of friendship seem to implicate more complex factors. For example, one function friendship seems to fulfil 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 (`birds of a feather') rather than those who would be complementary (`opposites attract'), a prediction which is supported by empirical evidence, at least so far as attitudes and beliefs are concerned.
In one 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 predictor of what friendships would be established by the end of four months, though it had less to do with initial alliances not surprisingly, since attitudes may not be obvious on first inspection.
There have also been studies of pairings, both voluntary (married couples) and forced (student roommates), to see which remained together and which split up. Again, the evidence seems to favour similarity rather than complementarity as an omen of a successful relationship, though there is a complication: 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 seems to become desirable. When a couple are not just similar but almost identical, something else seems to be needed. Similarity can breed contempt. it has also been found that when we find others obnoxious, 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 facets and therefore require a disparate 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.