A German scientist has calculated a formula for a happy relationship where criticism needs to be cancelled out by five compliments.

Dr Hans-Werner Bierhoff, from the social psychology department at the Ruhr University Bochum, claims that couples should ideally compliment their partners five times for each time they criticise them.

He said:”Then people feel good in their relationship. Goodwill increases your potential to be happy.”

Professor Bierhoff and his colleague Elke Rohmann conducted tests on thousands of individuals and couples and used the results to write a book called “What makes love strong” that provides advice on how relationships can be made to last.

The book also addresses problems that relationships can face as circumstances change.

He said that unemployment, infidelity or “stressful experiences” like diseases, depression or child birth can upset the balance and lead to a break-up.

More here.