New love interest may cost you two friends

Two close friends is the average price you pay for falling in love, scientists have discovered.

Research has shown that when people start a new romantic relationship they are likely to lose two members of their inner circle of friends. One is sacrificed to make way for the new partner, and the other disappears due to being ignored for too long, scientists believe.

Previous research has shown that friendships can wither if insufficient effort is put into maintaining them. Psychologists also know that people have "layers" of intimate and more distant friends. Typically, people have about five "inner circle" friends in whom they confide. It is these friendships that can be sacrificed for love, according to the new research outlined yesterday at the British Science Festival at Aston University in Birmingham.

Study leader Professor Robin Dunbar, of Oxford University, said: "When people are in a romantic relationship, instead of having the typical five inner circle friends, on average they have only four.

"Bearing in mind that one of those is the new person in your life, so it means you've had to give up two others."

The professor is famous for determining "Dunbar's number" - the maximum number of stable social relationships the human brain is theoretically capable of handling, which is said to be 150.