A Paradox

Satoshi Kanazawa discusses an interesting paradox in his blog, The Scientific Fundamentalist, over at the Psychology Today blogs:

One of my all-time favorites among all the scientific papers that I have ever read in my life is “Why your friends have more friends than you do,” published in the American Journal of Sociology in 1991 by my old sociology friend Scott L. Feld, who is now Professor of Sociology at Purdue University.

The title of Feld’s paper says it all, and here’s a little demonstration you can do to confirm his conclusion. List all of your friends. Then ask each of your friends how many friends they have. No matter who you are, whether you are a man or a woman, where you live, how many (or few) friends you have, and who your friends are, you will very likely discover that your friends on average have more friends than you do.

But how can this be? Friendships are bilateral (unless you are a stalker): If X is friends with Y, then Y is friends with X. How can Y and other friends of X have more friends than X does?

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This, incidentally, is the reason why a man often gets depressed after he has sex with a woman for the first time and then she tells him how many lovers she has had because she has had more lovers than he has. A mating version of Feld’s discovery may be termed “Why your lover has had more lovers than you have.” And the reason is the same.

Go read the blog to see an example and more discription of why this paradox is only apparent and not real. Your friends really do have more friends that you have!

I love these kind of mind benders.