Nov 18, 2021

Science shows how grandmothers’ brains respond to seeing their grandchildren

Science shows how grandmothers’ brains respond to seeing their grandchildren

People across the world treasure growing up with loving grandmothers, knowing how important and valuable that care and love was to their development from child to adult.

Excitingly, a new scientific approach has enabled scientists to scan grandmothers’ brains while showing them pictures of their young grandchildren – facilitating insight into the neural workings of this unique, intergenerational relationship.

The Proceedings of the Royal Society B has just published a first of its kind study looking into grandmaternal brain functioning, led by researchers at Emory University. 

Emory professor of anthropology and lead author of the study, James Rilling explains, “What really jumps out in the data is the activation in areas of the brain associated with emotional empathy.”

“[Emotional empathy] That suggests that grandmothers are geared toward feeling what their grandchildren are feeling when they interact with them. If their grandchild is smiling, they’re feeling the child’s joy. And if their grandchild is crying, they’re feeling the child’s pain and distress.”

However, when shown pictures of their adult children, grandmothers had a stronger activation in the region of the brain linked to cognitive empathy. Scientists believe this may highlight that the brain is trying to cognitively comprehend what their adult child is thinking or feeling and what’s underpinning that, but this brain functioning is not from the emotional region. 

Rilling continues, “Young children have likely evolved traits to be able to manipulate not just the maternal brain, but the grand maternal brain. An adult child doesn’t have the same cute ‘factor,’ so they may not elicit the same emotional response.”

Further members of the research team and study are co-authors Minwoo Lee, a Ph.D. candidate in Emory’s Department of Anthropology, and former Emory research specialist, Amber Gonzalez.

Drawing from personal experience Lee explains, “I can relate to this research personally because I spent a lot of time interacting with both of my grandmothers.” 

“I still remember warmly the moments I had with them. They were always so welcoming and happy to see me. As a child, I didn’t really understand why.”

Continuing, Lee says that it is fairly rare for scientists to examine the older human brain outside of the common research pursuits such as the problems of dementia or other disorders linked with aging.  

Outlining the importance of the study she says, “Here, we’re highlighting the brain functions of grandmothers that may play an important role in our social lives and development. It’s an important aspect of the human experience that has been largely left out of the field of neuroscience.”

The novel study happening in Rilling’s lab is no accident, as its focus has been on the neural basis of human social cognition and behaviour in unique areas. While motherhood has been a significant focus of other neuroscientists, Rilling has been a forerunner in studying the less examined neuroscience of fatherhood. 

It seemed fitting to pursue novel neural territory examining grandmothers interacting with grandchildren.

Rilling notes,  “Evidence is emerging in neuroscience for a global, parental caregiving system in the brain. We wanted to see how grandmothers might fit into that pattern.”

Studies have shown that humans are cooperative breeders, where mothers are provided assistance in caring for their offspring, however the sources of that support may differ between and within societies. 

Rilling says, “We often assume that fathers are the most important caregivers next to mothers, but that’s not always true. In some cases, grandmothers are the primary helper.”

Complementing this, the “grandmother hypothesis” asserts that the human females living significantly past their reproductive years is due to providing evolutionary benefits to their offspring and grandchildren. Data underpinning this hypothesis comes from a study of the traditional Hadza people in Tanzania, with grandmothers’ foraging was tied to nutritional improvement in their grandchildren. A further study shows traditional communities where grandmothers were present reduced their daughters’ interbirth intervals and elevated the number of grandchildren. 

In a range of measures including academic, social, behavioural and physical health, evidence has been building that links engaged grandmothers and their grandchildren to better outcomes in more modern societies. 

For the present study, scientists wished to comprehend the brains of healthy grandmothers and how that might be linked to positive outcomes they bring about for their families. 

50 grandmothers participated in the study, filling out questionnaires asking about their experiences in that role, detailing the time they spent with their grandchildren to the activities they shared and the level of affection they felt. 

Functional magnetic resonance imaging (fMRI) was conducted to examine their brain functioning as pictures of grandchildren were shared, as well as an unknown child, the same-sex parent of the grandchild and an unknown adult. 

Findings from the study highlighted that while seeing photos of their own grandchildren, the majority of participants displayed increased activity in the brain region that is linked with emotional empathy and movement, contrasted to when they were shown other images. 

Interestingly those whose brains showed higher activated areas involved with cognitive empathy when seeing photos of their grandchild, had stated in their questionnaire answers that they wished to be more engaged in caring for their grandchild. 

In summary, in contrast to the findings from a previous study by the Rilling lab, of fathers seeing photos of their children, the majority of grandmothers showed heightened activity in regions associated with emotional empathy and motivation when looking at images of their grandchildren. 

Rilling details, “Our results add to the evidence that there does seem to be a global parenting caregiving system in the brain, and that grandmothers’ responses to their grandchildren maps onto it.”

Researchers do acknowledge a limitation to the study in that the participants were predominantly physically and mentally healthy women who were high-functioning grandmothers. 

The researchers and study encourage more questions being raised and examined, Lee says, “It would be interesting to also look at the neuroscience of grandfathers and how the brain functions of grandparents may differ across cultures.”

Highlighting a particularly satisfying component of the project, Rilling was able to personally interview all the participants. He says, “It was fun. I wanted to get a sense of the rewards and challenges of being a grandmother.”

A core challenge many grandmothers brought up was restraining themselves from intruding into the approach of raising their grandchildren when they disagreed with their children, particularly in what values should be encouraged in their grandchildren. 

Rilling notes, “Many of them also said how nice it is to not be under as much time and financial pressure as they were when raising their children. They get to enjoy the experience of being a grandmother much more than they did being parents.”

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