Scientists believe they may have found the answer to why people first started living in communities ... religion.

A new study of near 600 people across six countries has found why people are honest and generous towards those who share their religion. It's because they fear punishment, or retribution from their god.

One of the study's authors, Auckland University's Quentin Atkinson, said they've found widespread co-operation is directly related to a shared fear.

"The idea is it might have been these kind of beliefs that helped humans transition from small hunter-gather groups to large agricultural societies."

LISTEN TO QUENTIN ATKINSON'S FULL INTERVIEW WITH MIKE HOSKING ABOVE