The Grandmother Hypothesis and Grandparents Day

The Grandmother Hypothesis and Grandparents Day

If you ask the evolutionary question: why do women continue to live after they are no longer able to bear, birth and breastfeed children, you come up with a researched and very interesting answer. They continue to be part of the evolutionary plan because they become grandmothers. And that is terribly important.


In the 1980s, anthropologist Kristin Hawkes and her colleagues studied the Hadza tribe, the last known hunter-gatherers in Tanzania, Africa. Their findings:

1. the tribe’s old women did not just rest, they worked, digging up a deeply-buried tuber which provided the main source of starch for the tribe’s diet.

2. though the young women also dug for the tubers, the older women spent more time at this task, leaving early in the morning and coming back late in the evening.

3. and because of the presence of this food in the diet, the grandchildren of these older women had better growth rates.

From these observations, came the “grandmother hypothesis.” Simply stated: women past childbearing age help not just their children, but their children’s children. They strengthen the genealogy of the family, insuring that the line will continue. Having such a role or purpose eventually lengthened their own life span. When no longer required to carry an infant around, they were freed up to do work that helped their progeny. And very importantly, by foraging for more food, they prevented their grandchildren from dying. All generations were aided as the lengthening of the life span was then passed on.

The researchers added that the “grandmother hypothesis” clarified why humans are able to have children in quick succession, whereas in other species there are long gaps. Example: chimp mothers wait 5 or 6 years to give birth to another neonate. But with tribal grandmothers available, the younger women could continue to have children. This collaborative child-rearing allowed the young woman to focus on the next baby while the grandmother took care of the toddlers.

In her piece in the New Republic that analyzes the “grandmother hypothesis” Judith Shulevitz writes of another very positive reason for grandmothers –As the grandmother effect spread throughout the population over thousands of generations, it changed humans in another way. It made their brains bigger. As life lengthened, so did each stage of it. Children stayed children longer, which let their brains develop a more complex neural architecture.


It is my belief that grandparenting is the most important family role of the new century, says Roma Hanks PhD. There is much to substantiate that claim. In a society where many women have to work or choose to work, daycare centers, schools and grandparents often replace the role of the parent. Hanks is referring to the gifts that grandparents can bring to children whose parents are stressed and often emotionally unavailable because of work schedules and the worry of providing basic needs. In these cases and in families where life flows more easily, grandparents are vital in helping a family thrive.

Children need guidance, love and someone to listen to their fears and worries. Grandparents easily become that source and a bond forms, allowing for future communication.
Grandparents can babysit, allowing stressed moms and dads a chance to get away and relate to one another.
Grandparents can relate family stories, creating a history that forges a bond and provides a child with a sense of place and security.
Grandparents can be a source of information, providing advice, guidance and just plain helping out–like locating the phone number of a doctor.
Grandparents can be role models for their children’s parenting and for their grandchildren’s relationships with others. The love and gentleness found in the home is the first step to forming good citizens of the world who will have their own relationships and build their own families in the decades ahead.
In the end, grandparents can offer a shoulder to cry on, words of encouragement, or gentle reassurance to both their children and their grandchildren.


Kate Fogarty, PhD, stressed the importance of the protective role grandparents can play when grandchildren are cared for by a depressed mother. Her research showed that the formation of loving bonds between grandparents and those children could help develop positive behavior, increase cognitive development and prevent behavioral problems. She even went so far as to say that the possibility of the depression being passed to these children could be broken by the grandparent/grandchild relationship–a win win.

And though Fogarty’s research was with grandparents, certainly the role of loving aunts, uncles and friends will always make a positive difference in a child’s life.


There’s the familiar line: “If I’d known how wonderful it is to have grandchildren, I would have had them first.” What is that all about? Probably that with grandchildren comes experience, confidence in the role to be played, freedom from the harder aspects of child-rearing and the amazing chance to see once again the future in a child’s eyes.

Certainly some grandparents have more nitty-gritty responsibility for their grandchildren than others. Some are doing much of the raising and rearing. Some show up only for the fun times, like birthdays and holidays.

But hopefully most grandparents find the middle acceptable ground–they are eager to role up their sleeves and help when needed and they are always desirous of telling family stories, reading well-loved books, taking exploratory walks or singing well-loved songs. It’s a little like reliving your parenting. It’s a lot like looking into the future and once again having that uplifting feeling of knowing something of you will live on. That’s truly important.

Celebrate Grandparents day, Sunday, September 11th, 2016

The Grandmother Hypothesis and Grandparents Day

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