In Brief
  • According to a Duke study, three year olds with the lowest 20 percent brain health grew up to commit over 80 percent of crimes as adults regardless of social class.
  • The results emphasize the need to give all children access to the resources necessary to ensure good brain health, such as public health and education programs.

Nature vs. Nurture

Many people debate whether criminality is a product of nurture or nature, but a new study published in Nature Human Behavior gives support to the latter argument, claiming that brain tests can predict a child’s inclination for criminal activity later in life.

Researchers led by neuroscientists at Duke University looked at data from a New Zealand study involving a thousand people in the early ’70s until they turned 38 years old. In that study, children as young as three years old completed a series of tests that measured their reflexes, language comprehension, motor skills, and social skills. According to the Duke researchers, the three year old subjects with the lowest 20 percent brain health grew up to commit over 80 percent of crimes as adults.

The researchers emphasize that brain health isn’t the only indicator for future criminality, noting that factors such as socio-economic status and child maltreatment can significantly impact adulthood behavior. To account for this, they did not include subjects living below the poverty line in their conclusions.

They also noted that the same 20 percent of subjects demanded the most from the state, accounting for “57% of nights in hospitals, 66% of welfare benefits, and 77% of fatherless child-rearing,” Quartz reports. “There aren’t so many children in middle class and wealthy homes who have poor brain health, but, where they are, they’ve also grown up to be very high cost users of public services,” says Terrie Moffitt, a professor of psychology and neuroscience from Duke University.

The data represent information about 940 people who were born in one hospital in the period 1972–1973 and are lifelong participants in the Dunedin Longitudinal Study. Image Credit: Nature

Early Intervention

Despite the potential implications of this study on the field of law enforcement, it’s important to note that it was not designed to help police find or monitor potential criminals. Ideally, this research would be used to identify at-risk children who can then be given early interventions before criminal behavior takes place.

The study also highlights the importance of ensuring that children, regardless of social class, are given access to the resources necessary to ensure good brain health. After all, while social class does have a significant impact on adult behavior, there is also a neurological aspect to it that can be addressed during a person’s formative years. “It’s really hard to improve social class. But child’s brain health, if you get in early, there’s a lot of demonstrations on how to improve that,” Moffitt adds.

Improving universal policies for public health and education for all children might be more cost effective than implementing programs intended to screen and identify at-risk children. The benefits of early intervention programs for all children (not just those that are deemed high-risk) could be significant. “Our study shows how bad things can be when children don’t get any help as pre-schoolers. That’s true of children who grew up in the 1970s but it doesn’t have to be true of children born in 2020,” says Moffitt.