The Lifelong Impact of Early Brain Development

Dr Felicia Low from Koi Tū: The Centre for Informed Futures, University of Auckland, outlines some fascinating results from recent research and what it might mean for policy making.

The human brain undergoes extraordinary growth during the early years of life. By the age of one, the brain has already more than doubled in volume, and by the age of two, it is 80 percent adult size. Specific brain pathways are developing that help us to achieve tasks such as focusing our attention, planning and organisation, controlling our impulses and interacting with others. These skills are known as ‘executive functions’. They help with successful learning, reasoning, problem solving, and long-term planning and are highly predictive of success in social, emotional, behavioural, and academic functions.

Impairments in executive functions place a person at greater risk of negative lifelong consequences, including school failure, poorer mental and physical health, job instability, antisocial behaviours, and poorer quality of life. The outcomes can also have intergenerational effects from parent to child. New Zealand studies show that measures of economic burden such as receiving social welfare support and having criminal convictions are disproportionately incurred by people with poor executive functions at age three. Impairments in executive functions therefore impose a large societal burden.

Studies have also found that impaired executive functions explains the relationship between child poverty and emotional and behavioural disorders in children and young people – and how poverty can disrupt long-term academic success.

Poor maternal mood during pregnancy is another risk factor. Recent research has shown that a woman’s mental wellbeing during pregnancy plays an important role in the development of her child’s executive functions. Children whose mothers had depression or anxiety while pregnant tended to show differences in brain structure and connectivity at birth and later displayed impaired executive functions as reflected in poorer school readiness and literacy skills. A further concerning observation was that impaired executive functions were also seen in children whose mothers experienced milder depressive symptoms, suggesting a large proportion of pregnancies may be affected.

The power of acting early

What can we do to promote optimal executive functions? Early intervention is the most logical and cost-effective approach to reduce the risks of lifelong disadvantages.

The finding that development of executive functions is affected by maternal mental wellbeing means that all pregnant women should be formally screened for their mood, and those who are affected – even to a mild or moderate extent – should be given support.

Another form of early intervention is intensive pre-school intervention programmes for young children at risk, such as the High/Scope Perry Preschool Study in the United States. These have been remarkably effective and have led to increased rates of high school completion, greater levels of employment, higher income, and reduced criminal activity and welfare reliance.

Unlike specific clinical disorders that can be formally diagnosed and treated with medication, impairments of executive functions require a very different understanding. It requires a population health focus on promoting brain health so that every child reaches their maximum capacity for learning, creativity, and productivity. This requires involvement across all domains of policy development, including health, social development, education, and justice. Evidence suggests that the priority issues to address are prevention of impairment, identification of the most at-risk children for early intervention, and development of evidence-informed policies on remediation.

In arguing for greater investment in early childhood development, Nobel laureate James Heckman noted that this is a rare example of public policy that can both reduce inequalities and improve society’s productivity without incurring trade-offs. The benefits to children, wider society, and future generations are unequivocal, but this can only be achieved with cross-sector, whole-of-government, and whole-of-society thinking.

This article is adapted from the evidence brief Executive functions: A crucial but overlooked factor for lifelong wellbeing by Felicia Low, Richie Poulton, and Peter Gluckman, published by Koi Tū: The Centre for Informed Futures, 2021.