Parents spanking children has rapidly fallen in popularity in recent decades, as science continues to show that it may not be the best form of punishment for misbehaving kids. However, a 2019 study suggests that spanking has not left many parents' book of punishments, with half of US parents spanking their children in the previous year and one-third spanking them in the previous week. Despite pediatricians and neurologists calling for a halt to the practice, it appears many US parents may still believe in it. 

Now, a new study from Harvard University published in the journal Child Development has found that spanking may be even more damaging to a child's development than previously thought. The researchers discovered that spanking children as a form of discipline could be altering their brain development in a similar way to more severe forms of abuse, sparking areas of their brain involved in threat perception and directly changing their decision-making. 

The altered brain development may have serious consequences on the child down the line. 

“We know that children whose families use corporal punishment are more likely to develop anxiety, depression, behavior problems, and other mental health problems, but many people don’t think about spanking as a form of violence,” said Katie McLaughlin, John L. Loeb Associate Professor of the Social Sciences and director of the Stress & Development Lab in the Department of Psychology at Harvard, in a statement. 

“In this study, we wanted to examine whether there was an impact of spanking at a neurobiological level, in terms of how the brain is developing.” 

The study delved into the brains of 40 children that had been spanked and compared them to a sample of 107 children that had not. Each child was asked to explain whether they had been spanked in the past or not, and also assessed on whether they had experience serious sexual or physical abuse.  

Once separated into groups, the participants were placed under an MRI scanner and shown actors' faces demonstrating different emotions for varying periods of time to see the brain activity of each child. 

The children who were spanked exhibited greater neural activity to the "fearful" faces, and this was also seen in children who experienced serious abuse, with no differences in brain activity between those two groups. These differences in reactivity show a strong similarity in the development of abused children and spanked children, which differs from those who were never struck. 

“While we might not conceptualize corporal punishment to be a form of violence, in terms of how a child’s brain responds, it’s not all that different than abuse,” said McLaughlin. “It’s more a difference of degree than of type.” 

As with many studies, this was not without limitations. It is impossible to quantify just how severely the children were spanked, and self-reporting of children can leave the study prone to under-reporting. These findings also do not explain why this difference is seen between spanked and non-spanked children, which is a job for future studies to understand. 

However, it does highlight some important developmental differences across parenting styles, and may challenge the current notion of whether corporal punishment is much different from violence.