A new Harvard study has claimed that being spanked can affect a child's brain development.
The study examined the effects of physical punishment - such as smacking and spanking - on the brains of 147 children and found that it can detrimentally affect a child's brain in the same way as "more severe forms of violence" and maltreatment.
Researchers discovered higher levels of activity in multiple regions of the prefrontal cortex (PFC) in spanked children, as well as in parts of the salience network (SN).
One of the study's authors, Katie A. McLaughlin from Harvard's Department of Psychology, said: "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.
"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."
Children aged 10 and 11 took part in the study, with the results being published in the Society for Research in Child Development Journal.
Each of the children were asked to lie in an MRI machine while being shown pictures of actors making "fearful" or "neutral".
Their brain activity was then mapped with the hope of being able to correctly identify patterns to distinguish who is smacked and who isn't.
The study authors wrote: "On average, across the entire sample, fearful faces elicited greater activation than neutral faces in many regions throughout the brain...and children who were spanked demonstrated greater activation in multiple regions of PFC to fearful relative to neutral faces than children who were never spanked.
"There were no regions of the brain where activation to fearful relative to neutral faces differed between children who were abused and children who were spanked."
It is legal to smack children in the US, but it was banned in Scotland in 2020 and it is set to be banned by Wales in 2022, the Daily Mail reports.
A "reasonable chastisement" defense currently exists in England, which means that smacking is legal providing that bruises, grazes, scratches, minor swellings, and cuts are not caused.
This, however, has been criticized as a defense as it means that it is acceptable to smack children, providing that no physical evidence is left behind.
Parents and caregivers could, for example, target body parts such as the head which are harder to mark, and therefore leave children with more serious injuries.
An NSPCC spokesperson said: "There is clear evidence that physical punishment damages children's wellbeing and is linked to poorer outcomes in childhood and adulthood.
"We would encourage parents to use alternative methods to teach their children the difference between right and wrong, with a positive parenting approach such as setting clear and consistent boundaries."
The study comes after previous research noted increased brain activity in children who have experienced abuse in response to threats, the Daily Mail reports.