Adversity in early life creates executive function challenges for children, research finds

by Freya Lucas

June 05

Children who experience adverse experiences or trauma in their early life are profoundly affected in many ways. Researchers have noted, in particular, the impact on a child’s executive functioning skills – that is, the ability to focus, organise tasks and to self regulate in order to achieve a goal.

 

Those children who experience poverty, residential instability, parental divorce or substance abuse, can also experience changes in brain chemistry, muting the effects of stress hormones.

 

Stress hormones typically support a child to face challenges, stress or to simply “get up and go”. The combined impact of adverse experiences and poor executive function create “a snowball effect” exacerbating the social and emotional challenges that can continue through childhood.

 

A new study by researchers at the University of Washington has examined how adversity can change the ways children develop. Lead researcher, Professor Liliana Lengua, said the study is demonstrating the way in which adversity impacts on multiple systems within a child.

“The disruption of multiple systems of self-control, both intentional planning efforts and automatic stress-hormone responses, sets off a cascade of neurobiological effects that starts early and continues through childhood,” she said.

The study, which was published in early May in Development and Psychopathology, looked at the lives of 306 children over a period of more than two years. When children first entered the study, they were around three years of age, with most of the participants exiting the study aged five and a half. The children studied came from a range of racial, ethnic and socioeconomic backgrounds, with 57 per cent of those in the study considered lower income or near poverty.

 

A key marker of adversity was parental income. Aside from income, the children’s mothers were surveyed about other risk factors that have been linked to poor health and behaviour outcomes in children, including family transitions, residential instability, and negative life events such as abuse or the incarceration of a parent.

 

Using the data gathered, Professor Lengua’s team tested children’s executive function skills with a series of activities, and, through saliva samples, a stress-response hormone called diurnal cortisol.

 

Cortisol tends to follow a daily and predictable pattern. In the morning, cortisol levels are higher, helping children and adults wake to face the day, dropping as the day progresses. In children and adults who are facing constant stress, however, a different pattern emerges.

 

“What we see in individuals experiencing chronic adversity is that their morning levels are quite low and flat throughout the day, every day. When someone is faced with high levels of stress all the time, the cortisol response becomes immune, and the system stops responding. That means they’re not having the cortisol levels they need to be alert and awake and emotionally ready to meet the challenges of the day,” Professor Lengua said.


To assess executive function levels, researchers chose preschool-friendly activities that measured each child’s ability to follow directions, pay attention and take actions contrary to impulse.

 

For instance, in a game called ‘Head-Toes-Knees-Shoulders’, children were told to do the opposite of what a researcher told them to do — if the researcher said “touch your head,” the child was supposed to touch their toes. In another activity, children interacted with two puppets — a monkey and a dragon — but were supposed to follow only the instructions given by the monkey.

 

When children are better at following instructions in these and similar activities, they tend to have better social skills and manage their emotions when stressed. Children who did well on these tasks also tended to have more typical patterns of cortisol.

 

But children who were in families that had lower income and higher adversity tended to have both lower executive function and an atypical cortisol pattern. Each of those contributed to more behaviour problems and lower social-emotional competence in children when they were about to start kindergarten.

 

The results demonstrated that not only do low income and adversity affect children’s adjustment, but they also impact these self-regulation systems that then add to children’s adjustment problems. “Taken all together, it’s like a snowball effect, with adverse effects adding together,” Professor Lengua said.

 

While past research has pointed to the effects of adversity on executive function, and to the specific relationship between cortisol and executive function, this new study shows the additive effects over time.

“Executive function is an indicator that shows the functioning of cognitive regulation. Cortisol is an automatic response, and the two consistently emerge as being related to each other and impacting behaviour in children,” she noted.

Researchers said they would like to see their work inform parenting programs, early childhood and school-based interventions. Safe, stable environments and communities, and positive, nurturing parenting practices support child development, while a focus on relationships and healthy behaviours in preschool settings can support children of all backgrounds, regardless of their experiences of adversity.

 

For more information, or to read the study in full, please see here.

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