But is it true? It took a maverick social psychologist called Stanley Milgram to conduct the first scientific test, back in 1967, of whether we live in a small or a big world. It should be pointed out here that Milgram was one of the most interesting and controversial figures ever to grace American academic life. Before he dreamed up his small world study, he was already quite famous–or rather notorious–as the American professor who electrocuted his students. Well, almost. In a series of gripping experiments at Yale University in 1961–2, Milgram got white-coated experimenters to take charge of volunteers in ‘a study of memory and learning’. Some of the volunteers took the role of ‘teacher’, who would help the ‘learner’, who was strapped into a chair. If the learner couldn’t remember the right answer, the teacher was supposed to administer a small electric shock. Moreover, the teacher was told to ratchet up the voltage if the learner continued to give the wrong answer, until they screamed out in agony.
Now, the learners were really actors and there was no electricity. But the teachers didn’t know that. The point of the experiment was to see how far they would go in administering pain when instructed to do so by the white-coated psychologists who represented ‘authority’. The answer, in many cases, was disturbing. Most of the teachers dispensed what they thought were ever greater electric shocks, and a substantial proportion continued to the highest level, which was marked ‘danger’, despite the anguished cries of the learners. In his 1974 book Obedience to Authority, Milgram explicitly compared the behaviour of the Yale students to that of Nazi concentration camp guards.
We’ll come back to this experiment later, but for now take it as a glimpse into the fertile mind of the man who went on to investigate the idea of the small world. Reporting his results in a fascinating article in the first ever issue of Psychology Today, he starts with a story:
Fred Jones of Peoria, sitting in a sidewalk café in Tunis, and needing a light for his cigarette, asks the man at the next table for a match. They fall into conversation; the stranger is an Englishman who, it turns out, spent several months in Detroit studying the operation of an interchangeable-bottlecap factory.
‘I know it’s a foolish question,’ says Jones, ‘but did you ever by any chance run into a fellow named Ben Arkadian? He’s an old friend of mine, manages a chain of supermarkets in Detroit…’
‘Arkadian, Arkadian,’ the Englishman mutters. ‘Why, upon my soul, I believe I do! Small chap, very energetic, raised merry hell with the factory over a shipment of defective bottlecaps.’
‘No kidding!’ Jones exclaims in amazement.
‘Good Lord, it’s a small world, isn’t it?’
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We might quibble that the story is clearly fictitious and the dialogue stilted–an Englishman abroad in 1967 was unlikely to have said ‘upon my soul’, a phrase more redolent of the novels of Evelyn Waugh. No matter. The reader is drawn in and Milgram goes on to explain exactly what he’s trying to test: whether the world really is ‘large’ or ‘small’. If it truly is a small world, then Jane Jacob’s Messenger game would work with a relatively small number of personal links. The small-world view sees acquaintances as stepping stones or connecting links to any person or group we want to reach. In a later article, Milgram and a collaborator amplified this view eloquently: ‘The phrase “small world” suggests that social networks are in some sense tightly woven, full of unexpected strands linking individuals far removed from one another in physical or social space.’4
By contrast, a large world would mean that there are mainly unbridgeable gaps between people, with everyone pretty much confined to their own social or local existence. These diverse groups will never meet because they don’t intersect. A message will stay trapped within the group, like a fly in a corked bottle, and will never be able to jump out, because nobody is a member of two such groups; there is no common link.
To determine which view was correct, Milgram had the bright idea of selecting participants from two cities–Wichita, Kansas, and Omaha, Nebraska–and seeing if they could pass a folder on to someone they knew on a first-name basis, who would then mail it to someone they knew, and so on until it reached a ‘target person’. In the Kansas study the target was the wife of a divinity school student in Cambridge, Massachusetts; in the Nebraska study it was a stockbroker in Boston. Each of the intermediaries in the chain would endeavour to get the folder as close as possible to the target via people they knew personally. Milgram reasoned that if the process worked at all it would provide evidence of a small world; then, the fewer the links, the more the small-world thesis would be upheld. Along the way, since the identities of the intermediaries were tracked, a great deal would be learned about how networks operated.
The first completed chain came in the Kansas study, as Milgram explained:
four days after the folders were sent…an instructor at the Episcopal Theological Seminary approached our target person on the street. ‘Alice,’ he said, thrusting a brown folder towards her, ‘this is for you’…[W]e found to our pleasant surprise that the document had started with a wheat farmer in Kansas. He had passed it on to an Episcopalian minister in his home town, who sent it to the minister who taught in Cambridge, who gave it to the target person.
So just two intermediate links had been necessary, making this one of the shortest chains to be completed.
The Omaha test produced a more typical result. Here, a widowed supermarket clerk passed the folder to a friend who was a painter in Council Bluffs, Iowa. He sent it on to a publisher in Belmont, Massachusetts, who forwarded it to a tanner in Sharon, the suburb of Boston where the target stockbroker lived. The tanner then gave it to a sheet-metal worker, also in Sharon, who handed it to his dentist, who passed it to a printer, who gave it to a clothes retailer, all still in Sharon, who finally delivered it to the stockbroker. So this time there were seven intermediaries, not counting either the starting or the target person.
In the Psychology Today article, Milgram gives data on the Nebraska study. One hundred and sixty chains were started and forty-four were completed. The number of intermediaries in the completed chains varied between two and ten. He also mentions another twenty chains completed in an auxiliary study, originating in the Boston area, also targeted at the local stockbroker. Combining the studies, the average number of links in the sixty-four completed chains was five intermediaries. Though Milgram never mentions ‘six degrees of separation’, his experiment appears to be a remarkable vindication of the idea, at least for the United States, if not for the whole world.
Small world proven? An open and shut case? Milgram clearly thought so. And commentators took him at his word, with no lingering doubts about either this or his earlier ‘electrocution’ experiment. Until, that is, another psychologist, Judith Kleinfeld, came on the scene in 2002. The story goes that she was impressed with the experiment and wanted her students to replicate it using email, but as she investigated Milgram’s working papers she became increasingly disturbed that he had drawn unwarranted conclusions. ‘Milgram’s findings’, she wrote, ‘have slipped away from their scientific moorings, and sailed into the world of imagination. The idea of six degrees of separation may, in fact, be plain wrong–the academic equivalent of an urban myth.’5 This is as close as the genteel world of academia comes to crying, ‘Fraud!’