Forging strong social relationships can help mitigate the effects of traumatic childhood events in adult humans, as well as baboons. a study published May 17 in the journal Scientific progress drew on 36 years of data from nearly 200 baboons in southern Kenya and found that while early adversity can take years off their lives, stronger social bonds in adulthood can help regain those years.
[Related: Baboon poop shows how chronic stress shortens lives.]
“It’s like the saying of the King James Apocrypha, ‘A faithful friend is the medicine of life,'” co-author and Duke University biologist and evolutionary anthropologist Susan Alberts said in a statement.
Studies have consistently found these are people who experience more bad experiences during their childhood, such as neglect or abuse more likely to die early. However, the mechanisms behind how early adversity leads to premature death are harder for researchers to pin down, Alberts says. Some of the limitations of previous research include the reliance on self-reported memories which can be imprecise and subjective.
Enter our primate cousins. Baboons share more than 90 percent of their DNA with humans and researchers have been tracking individual baboons near Amboseli National Park in Kenya since 1971.
In this new study, the researchers analyzed how early life experiences and mature social connections influenced long-term survival in 199 female baboons between 1983 and 2019.
Baboon childhood is certainly different from human childhood, but young baboons still face hardships. The team in the study counted each woman’s exposure to six possible sources of early adversity, including whether she had a low-ranking or socially isolated mother or whether her mother died before reaching adulthood. It was also noted whether she was born in a dry year or in a large group, and whether she had a sibling who was about the same age, which could contribute to increased competition for both maternal attention and resources.
The team found that stressful experiences are common for the baboons growing up in the semi-arid and unpredictable landscape of Amboseli. Of the 199 baboons in the study, 75 percent experienced at least one stressor and 33 percent experienced two or more.
Their results confirm previous findings that the more hardship a female baboon encounters, the shorter her lifespan. Monkeys that experienced more agitation at a young age were also more socially isolated as adults.
[Related: Monkeys with close friends have friendlier gut bacteria.]
However, the researchers showed that 90 percent of the dip in survival was due to the direct effects of early adversity, not the weakened social bonds that continued into adulthood.
However strong their bond with other baboons, each additional hardship translated into 1.4 years of life lost. Those who had four bad experiences growing up died nearly 5.6 years earlier than those who had none. Since the average female baboon lives to be 18 years old, this is a big drop in lost years.
But an unlucky start in life doesn’t mean a baboon will definitely have a short life.
“Women who live bad lives are not doomed,” co-author and biologist at SUNY Oswego Elizabeth Lange said in a statement. “We found that both early life adversity and adult social interactions independently influence survival. That means interventions that take place throughout life can improve survival.
In baboons, strong social bonds are measured by how often they interact with their closest friends. Those with strong social ties added 2.2 years to their lives, regardless of the adversity they experienced in their earlier years. The baboons whose mothers died before reaching adulthood and then forged strong friendships in adulthood showed the best ability to bounce back.
However, the flip side is also true. According to the study, weak social ties may increase early life adversity.
It is not yet clear whether these results translate to adult humans, but it suggests that early intervention is not the only way to overcome childhood trauma and its lingering effects.
“If you’ve had adversity in your early life, try to make friends whatever you do,” said Alberts.