The Small World Experiment

In June 2003, Prof Wiseman published an article in The Daily Telegraph about his research into luck and the 'small world' phenomenon, reproduced here:

Most people have encountered the "small world" phenomenon - that striking coincidence that emerges while chatting to a stranger at a party when you discover that the two of you have a mutual friend or acquaintance.

Many scientists now believe that almost any two strangers, selected at random from anywhere in the world, may well be linked by an amazingly small number of people - half a dozen or so.

We know that the internet, the brain, the web of reactions in a living cell, power grids and the economy are other examples of this connectedness. In short, scientists believe that we live in a genuinely small world.

But what evidence is there to support this view? Not as much as you might think, for an idea that has been around for decades. To test the idea, and to see if some people live in smaller worlds than others, Prof Wiseman designed an experiment with The Daily Telegraph and the Cheltenham Festival of Science.

Working with the Telegraph's science editor, colleagues at the festival and Dr. Emma Greening of the University of Hertfordshire, We conducted the first British experiment to explore the phenomenon, one that is also relevant to the psychology of luck.

Our experiment was based on an ingenious study carried out in the 1960s by American psychologist Stanley Milgram. Milgram sent letters to just under 300 randomly selected people in Nebraska and Kansas, asking them to help ensure that the letter made its way to a "target person" - a named stockbroker in Boston.

Participants were asked not to send the letter directly to the stockbroker. Instead, everyone was allowed to send it only to someone whom they knew on first-name terms and who they thought might know the stockbroker.

Twenty-nine per cent of the parcels eventually reached the stockbroker. Amazingly, given the tens of millions of people in America, there tended to be just six people linking the initial volunteer and the target person - thus giving rise to the popular notion that we are all maybe connected by just six degrees of separation.

Our experiment explored whether Milgram's findings withstand scrutiny in modern Britain, with its population of about 60 million people. Earlier this year, we published an article on Connected, inviting readers who wished to participate to contact me.

More than 500 readers replied, a great response. One hundred were randomly selected and were then sent a package containing postcards, envelopes and instructions explaining that the purpose of the experiment was to ensure that the parcel made its way to a certain target person.

Rather than using a stockbroker in Boston, our target person was Katie Smith, a 27-year-old events organiser working in Cheltenham. Participants were simply told that Katie studied history of art at Manchester University, once worked in public relations in London and enjoys cycling.

As with Milgram's original study, all initial volunteers and subsequent recipients were asked to send the parcel only to someone they knew on first-name terms. Everyone was also asked to return one of the postcards to us, so that we could track the packages as they moved around the country.

Ten per cent of our parcels eventually reached Katie. Amazingly, there tended to be just four people linking our initial volunteers with Katie - two fewer than in Milgram's experiment. Some of the chains in our study provide striking illustrations of just how well-connected apparent strangers actually are.

For example, one of our initial volunteers was Barry, a textile agent from Stockport. Perhaps not surprisingly, Barry didn't know Katie, and so sent the parcel to his friend Pat because she lives close to Cheltenham Racecourse. But Pat didn't know Katie either. However, she passed the parcel to her friend David because he is chairman of the Cheltenham Festival of Science. Bingo! David knows Katie and so was able to pass the package directly to her and complete the chain.

The especially small number of people linking our volunteers to Katie suggests that present-day Britain is indeed a much smaller world than America in the Sixties. In addition, it supports the idea that we may indeed all be linked to one another via a remarkably small number of people. The experiment also explored whether certain people might be especially well-connected. In January we published The Luck Factor, a book summarising more than a decade of research into why some people lead exceptionally lucky and unlucky lives.

This work revealed that lucky people frequently experience the small-world phenomenon, and that such "lucky" meetings have a dramatic and positive effect on their lives. In contrast, unlucky people rarely report such experiences.

We speculated that lucky people report lots of small-world experiences because they know a large number of people, and so are more likely to be linked to the strangers they encounter. They are, without realising it, making their own luck by developing lots of connections with others, dramatically increasing their chances of having beneficial small-world encounters.

To test this idea, we asked each volunteer to rate his or her general level of luckiness prior to taking part in the study. We monitored how many lucky and unlucky people actually sent on the package. Approximately 20 did not send their parcels at all, guaranteeing that their packages would never reach Katie. Interestingly, the vast majority of these people had previously rated themselves as unlucky.

We wanted to discover what lay behind such behaviour. These volunteers had gone to considerable lengths to ensure that they participated in the study, but had then dropped out at the very first stage.

We wrote to ask each why they had failed to send on the parcel. Their replies were telling - most said they couldn't think of anyone whom they knew on first-name terms and who could help deliver the parcel to Katie.

Thus the lucky participants were far more likely to know potential recipients for the parcels than unlucky people, so were far more successful when it came to sending on their parcels. Indeed, all of the people in the amazingly short chain started by Barry rated themselves as very lucky.

These results provide support for the notion that lucky people are living in a much smaller world than unlucky people and that this, in turn, helps maximise their potential for "lucky" small-world encounters in life.

Our study was the first British replication of Milgram's experiment. The results suggest that the world has indeed become substantially smaller over the past 40 years.

Perhaps, as a result of vast increases in electronic communication, telephone networks and travel, we are all connected to one another as never before. Maybe, on a social level, science and technology have genuinely shrunk the world.

Read the original article on the Telegraph website here.