A recent study shows that the amount of social interaction between extended family members depends on whether people are related through their mother or father.

Thomas Pollet and colleagues at Newcastle University and the University of Antwerp, Belgium, investigated how far maternal grandparents and paternal grandparents will go to maintain face-to-face contact with their grandchildren. They found that maternal grandparents were willing to travel further in order to sustain frequent (daily or a few times a week) contact with their grandchildren than paternal grandparents.

Mr Pollet says, "As the festive period approaches, we can still see that family get-togethers are integral to the celebrations. Many people will be going the extra mile to ensure they meet up -- and we've found that's particularly important if family members are related through mothers."

"Even in families where there has been divorce, we found consistent differences -- grandparents on your mother's side make the extra effort. We believe there are psychological mechanisms at play because throughout history, women are always related by maternity whereas men can never be wholly certain they are the biological father to their children."

The authors interpret their findings as support for psychological patterns resulting from our evolutionary history. Family members related through their mothers (matrilineal kin) are predicted to matter more than those related through their fathers (patrilineal kin). Throughout human evolution, women were always related by certain maternity, whereas men could never be wholly certain that they are the biological father. Also, maternal grandparents were always more certain than paternal grandparents that a grandchildren was related to them. Thus, maternal grandparents, especially maternal grandmothers, may go the extra mile to visit their grandchildren.

For grandparents living within 19.5 miles (30 km) of their grandchildren, over 30% of the maternal grandmothers had contact daily or a few times a week. Around 25% of the maternal grandfathers had contact daily or a few times a week. In contrast, only around 15 % of the paternal grandmothers and little more than 15% of the paternal grandfathers would have contact daily or a few times a week.

The research which is published in the latest edition of the journal Evolutionary Psychology, was conducted on a sample of over 800 grandparents from a representative Dutch sample. The analyses controlled for other factors such as grandparental and child age, marital status, and number of children.

The study is in the current issue of the journal Evolutionary Psychology.

Note: If no author is given, the source is cited instead.

• Child Psychology
• Child Development
• Schizophrenia
• Social Psychology
• Stress
• Gender Difference

• Maternal bond
• Human bonding
• Fetal alcohol spectrum disorder
• Aggression
• Social cognition
• Erikson's stages of psychosocial development