It’s long been known that early childhood experiences can have a profound affect on later opportunities and life chances. Now, a collection of new studies suggests that those experiences may actually affect the size and workings of the brain.
The studies were or are being presented this week at the annual meeting of the Society for Neuroscience. Together, they provide a glimpse into how much childhood environments may matter — from the number of books in a home, to exposure to abuse, to economic status.
One study showed a correlation between parental educational and economic status and later brain capacity in certain regions involved in memory and cognitive control. The greater the income levels, the more hippocampal (crucial for learning and memory) volume; the higher the educational level, the less volume in the amygdala (where stress is processed).
The results, according to Suzanne Houston, a researcher at University of Southern California who is presenting the work to colleagues today, were not explained by differences in gender, age or race. There’s a more likely link with exposure to stress and language use at home.
Another study found that children exposed to abuse at a young age as adults exhibited “enhanced stress response.”
Lead author Layla Banihashemi, a post-doctoral scholar at the University of Pittsburgh, noted that the more intense brain reaction to stressors left these adults more vulnerable to later physical and mental health problems.
A third study found that adults who grew up in poverty showed more memory deficit than others from different economic backgrounds.
The lead author, Eric Pakulak, a research associate at the University of Oregon’s Brain Development Lab, said the team also found that if parents and children from lower-income families participated in an eight-week training session — parents received training in stress reduction and children in attention — their memory development improved significantly.
And still another study found that relatively minor differences in the home environments of young children might affect their later brain development.
For that study, researchers tracked a group of 53 children from families on the lower end of the socioeconomic scale over the course of 20 years. Research teams visited subjects when they were 4 years old and 8 years old, noting details like the number of books in the home, if a child’s artwork was displayed, if the parent introduced the child to a visitor. More than 10 years later, the teams used neuroimaging, among other techniques to compare the structures of subjects’ brains.
They found that “childhood home environment predicts frontal and temporal cortical thickness in the young adult brain.”
In other words: The findings, “provide powerful evidence that even relatively minor variations within the normal range of home experience can affect brain development over a lifetime,” said Brian Avants, an assistant professor at the University of Pennsylvania who led the study.
The researchers did not find similar brain development in connection with parental nurturing, such as how often a parent held or talked with the child.
Martha J. Farah, the director of the Center for Neuroscience & Society at the University of Pennsylvania, who also worked on the study, cautioned that parents not read too much into the results.
“It’s exciting because virtually all previous evidence concerns pathological extremes of experience (abuse, neglect, institutionalization) so it’s a first look at the effects of experience in the normal range. And it is of interest scientifically because it highlights certain brain areas as sensitive to these experiences, shows that these areas respond more to cognitive stimulation than to warm supportive parenting, and suggests that they are more affected by early rather than later experience,” she said.
“But it’s a long, long way from those findings to any practical advice to parents. Yes, it’s nice to see nice hard brain data showing that activities like reading to your young children makes a difference. … [But], obviously you don’t want to conclude that you can be cold and mean to your child because the parental nurturing measures didn’t predict cortical thickness in these specific brain areas.
“I see this as a first step down a long road that may eventually yield information that can inform parenting practices.”