The EXACT number of friends you need to be successful revealed

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A behavioural psychologist has revealed the exact number of friends you need to be successful - and why having too many can be just as bad as having none.

British anthropologist and 'mathematician of relationships' Robin Dunbar believes we can only maintain a certain number of human connections at any one time.

In his latest book, Friends: Understanding the Power of our Most Important Relationships, the 73-year-old dissects scientific research into human groups to determine that 150 is the 'magic number' needed for success.

Mr Dunbar discovered that historically, 150 was the preferred grouping found in factories, small villages and and military units, where everyone knows each other's names and skills and are willing to help each other when needed.

a group of people sitting on a bench: British anthropologist and 'mathematician of relationships' Robin Dunbar believes we can only maintain a certain number of human connections at any one time (stock image) © Provided by Daily Mail British anthropologist and 'mathematician of relationships' Robin Dunbar believes we can only maintain a certain number of human connections at any one time (stock image)

Robin Dunbar's tiers of friends

Intimate friends: 5 (who would donate a kidney to you)

Supportive friends: 12 to 15 (who would be distraught if you died)

Good friends: 50 (who would be invited to your birthday party, but not a dinner party)

Regular friends: 150 (who you meet at weddings and school reunions)

Source: Friends: Understanding the Power of our Most Important Relationships by Robin Dunbar

The EXACT number of friends you need to be successful revealed