As the “effect of grandmother” has helped increase human life expectancy

By Haider Warrich

Not long after our first child was born, my wife and I spoke to my mother in Pakistan to ask if she could come and stay with us for a while in Durham, North Carolina, where I was specializing to be a cardiologist.

When she agreed, we were overjoyed. But when she went to the airport to depart, she learned that her visa had been cancelled for no official reason. The fact that she could not come to see her only granddaughter (and help her parents) was very stressful for all of us.

But, as mentioned in some recent articles published in the magazine “Current Biology”, the presence of grandmothers in the life of a young child goes beyond sentimental impact: They can be responsible for the success of human species.

At first, few stories: evolutionary biologists have long been impressed by two unique human traits. First, we're among the longest living creatures in the animal kingdom. In the last 200 years alone, there has been an unprecedented increase in human life expectancy, not only in richer countries but also in poorer ones.

We've moved so far from our hunting-gathering ancestors that their life span is more like that of monkeys and chimpanzees than modern human beings.

This feature is associated with another. For a biologist, an organism that cannot be reproduced has little value in evolutionary terms.

Scientists are therefore surprised by the long life of women after menopausis. From a purely evolutionary perspective, the grandmothers can be seen as a failure of reproductive ability: and what good is there in an organism that cannot be reproduced, and can't help the continuation of its species?

However, as most recent studies confirm, grandmothers not only can help preserve species but can be one of the reasons why people today have a much longer life than they used to. Women were once thought to be single mammals, with a long post-reproducing phase of life.

Scientists have identified other mammals, such as orcs, with long life periods of postproductive life. It turns out that these two features, the long life of man and the long post-productive life of women, can be connected through the “effect of Grandma”

Evolutionary biologists have shown that many women who were once thought to be evolutionary avoidance can be the key to human life span. Helping to raise their grandchildren, grandparents in hunting societies (and even more modern) allowed their daughters to have more babies.

Mathematical simulations have shown that the <x0 effect of Grandma”, introduced in 1966, is an important reason why human life expectancy moved from a model similar to that of monkeys to present in modern and primitive societies.

The reasoning is more or less: By facilitating a mother from some of the responsibilities of raising her children, grandmothers make it easier for their daughters to have more children and also allow them to have a longer life, helping them through the difficult years of early life.

Two new studies, published in “Current Biology”, reinforce this concept. An analysis of church data and death in Finland for individuals born between 1731-1890 showed that having a grandmother between 50 and 75, when her grandson was 5 or younger, increased the chances of child survival.

That effect disappeared, for grandmothers older than 75 years, maybe because they may not have been able to help with child rearing. The effect on people's life expectancy, it's been seen mainly by mothers and not by fathers.

The second study pauses to this effect, showing that it is not just the existence of a grandfather but its proximity that is of utmost importance. The shorter the distance between Grandma and grandsons, the more their grandmother gets involved in their lives, and so does the benefits for her daughter and grandchildren.

These new studies strengthen the pre-existing argument for grandmothers, showing how important they can be to the success of our species. In some ways, though, we are at a crossroads. For centuries, grandmothers have helped to raise their own family offspring.

Today, many families live alone without grandparents. During the 20th century, the core family has been transformed, with some of the biggest changes resulting from geographical distribution. At the beginning of the 20th century, only 7 percent of older women lived alone. This peaked at 38 per cent in the 1990s, and is officially about 32 per cent.

If this distribution continues, we can change the evolutionary role that the grandmothers played, and they can lose the benefits we've achieved from this effect. What needs to be changed is not only a greater understanding of the role that grandparents can play but also a growing effort to return to the units of the multinational family.

Such a move would help mothers and grandmothers, especially when the latter gets older and requires self - care. But modern families, should not only care about grandmothers, writes the world.al, broadcasts the Kosovo Clan. Part of the equation, there must be grandparents. Like fathers who have taken a role in raising children, grandparents should have a role. Children raised in multi - Jewish families have better results at school and fewer emotional and behavioral problems than those living in a family of just two generations.

After Barak Obama's parents divorced, he spent several years living with his grandparents in Hawaii. His education represents a remarkable example of grandparents who did a wonderful job in raising their grandson, especially when the parents ' situation is complex.

Although we think of new ways to raise and educate our children, we have to preserve some old ways, and do what we can to prevent the change of Grandma's <x0-effective”, which has been so important for the growth of the human species.

Our daughter, Eva, is now three years old, and my wife and I are still not ready to have another child. It's all we have - our love and our attention, but our time and energy. However, what might change the equation would be if my mother could get a visa and come to the US.

While our family and others stand at the sudden intersection of the schizophrenic policies of migration and evolutionary biology, and we seek what is best for the future of our children, science would suggest that we should start looking to the past.