When you go to a conference where you don't know anyone, do you just wander up to the first person you see or do you do your homework, have a good look at the delegate list and plan who you speak to - and indeed sit next to?

I saw Wild Hogs recently, a movie about a bunch of ageing friends who go on one last road trip together across the wastelands of the American Mid West on Harley-Davidsons. It's rather like the reunions my old university pals and I hold - although we don't own motor bikes, we meet up in the wastelands of Berkshire, and tend to just stay put in a comfy hotel.

The point is all six of us met on the very first day of university and have remained firm friends ever since. And that's despite sharing a flat in Newcastle for three years, with the inherent squabbling and subsequent deep resentment over cooking rotas .

Our children think it's amazing our friendships, formed on the very first day of university, should last for more than thirty years. But is it so unusual? A recent study gives us the answer. Dr Mitja Back subjected brand new psychology students to a nerve-wracking first day. At their introductory session, they were told to sit randomly. Then each fretting fresher had to introduce themself from the podium. Immediately after, everyone else was asked to rate that person on two scales: how much they liked them and whether they would like to get to know them more.

The results showed that people liked - and wanted to be friends with - the people who they initially sat next to. However, the most interesting results were revealed one year later when the students were well settled into the course, had mixed extensively with other students, and knew each other much better. Surely that first day when the lecturer tortured them with random seat allocations, public introductions and instant judgements wouldn't still be influencing their friendships? It was. Even after a year, students who sat on the same row on that first day liked each other better. And for those who sat right next to each other, the level of liking was even higher.

Why should this be? Well perhaps when we're put in a brand new social environment we're anxious to make a connection with someone. Anyone. And when we find someone to talk to - an island of acceptance in a sea of strangers - we're so relieved that we're more likely to form a lasting bond.

So in future, if you go to a conference and don't know anyone, be selective about whom you first introduce yourself to. You may be with them for a very long time... n

Professor Philip Hesketh is a professional speaker on the psychology of persuasion and author of the Amazon best selling book Life's a Game So Fix the Odds. www.heskethtalking.com