The actor Sir Peter Ustinov once famously said "Contrary to general belief, I do not believe that friends are necessarily the people you like best, they are merely the people who get there first." Psychologists now believe there is some truth to this argument.

Rather than picking our friends based on intentional choice like common values and interests, our friendships may be based on more superficial factors like proximity or group assignments, like a department where you work or even an entirely new job.

Mitja Back, Stefan Schmukle, and Boris Egloff of the University of Leipzig sought to test the notion that random proximity and random group assignment at zero acquaintance would foster friendship in the long run. The researchers investigated 54 college freshmen upon encountering one another for the first time at the beginning of a one-off introductory session and randomly assigned them a seat number in a group of chairs organized in rows.

They wrote of their results in a recent issue of Psychological Science, stating that sitting in neighboring seats as a result of randomly assigned seat numbers when meeting for the first time led to higher ratings of friendship intensity one year later. The same was true even if participants were merely in the same row.

The counterintuitive finding suggests that friendships may not be as deliberate we think.

"In a nutshell," write the authors, "people may become friends simply because they drew the right random number."