Worldwide, there are only 60 countries that ban the use of corporal punishment on children in the home. These include Brazil, Kenya, New Zealand, and Sweden, which was the very first country to outlaw the practice outright in 1979. Meanwhile, in the UK, countries like Wales and Scotland are in the process of passing legislation to restrict or ban smacking altogether.
Cross the Atlantic Ocean and NPR reports that 28 states (and DC) prohibit the use of corporal punishment in schools and seven do not. That leaves 15 states that explicitly permit corporal punishment, including Texas, Florida, and North Carolina.
According to a 2017 ABCNEWS poll, spanking children in school is supported by little over a quarter of US adults (26 percent), but many more (65 percent) approve of spanking as a form of childhood discipline in general, presumably provided it remains in the home. This figure has remained relatively stable since 1990.
However, the expert opinion – at least from those at the UK Association of Educational Psychologists (AEP) – is that regular spanking is not only ineffective (there are few reliable studies to show it dissuades future bad behavior) but it can damage the health of children and adolescents. No doubt there will be the inevitable chorus of "well, it didn't do me any harm", but the scientific research so far suggests that's not always the case.
The largest study to date (actually a meta-analysis) involving 75 papers over a 50-year period and more than 160,000 children found that spanking is associated with 13 out of 17 measured outcomes, including poorer mental health in childhood and adulthood and higher levels of antisocial behavior.
However, the findings are seen as somewhat controversial. The American College of Pediatricians released a statement in response to the research, calling the analysis "woefully inadequate" and criticizing the researchers for relying too much on correlational data and ignoring "the beneficial findings of studies that have investigated appropriate ways of spanking in disciplinary situations traditionally considered appropriate."
Nonetheless, young brains are especially pliable and these are just a handful of the ways spanking can have an effect.
An admittedly small-scale study published in the Annals of Global Heath earlier this year on 74 pairs of caregivers and their children found that spanking (and scolding, for that matter) was linked to developmental delays. In fact, children regularly spanked were five times as likely to experience language delays, though whether the spanking caused the language delays or vice versa (or whether there's a third factor involved somewhere) is a little trickier to determine, so the results need to be taken with a grain of salt.
Reduced grey matter:
A 2009 study found that corporal violence was also associated with a significant reduction in grey matter, a tissue responsible for translating the sensory information we receive into chemical data our brain can understand. It is involved in everything from hearing to speaking to our emotions and self-control. But those who had been regularly spanked as children showed a 19.1 percent decrease in gray matter volume in the right medial frontal gyrus, 14.5 percent in the left medial frontal gyrus, and 16.9 percent in the right anterior cingulate gyrus.
Poorer mental health:
A 2012 study involving 34,600 US adults found that 2 to 7 percent of mental health disorders could be attributed to corporal punishment, specifically major depression, anxiety, and paranoia. Six percent of respondents reported being "pushed, grabbed, shoved, slapped or hit" by their parents and those that had were 59 percent more likely to be alcohol dependent, 41 percent more likely to have depression, and 24 percent more likely to have a panic disorder (again this is an association, not a cause-effect link). Which leads to...
Booze, drugs, and suicide:
In a 2017 study, researchers surveyed more than 8,000 adults aged 19 to 97 about their childhood history with spanking – the results were shocking. Those who had been spanked were 23 percent more likely to engage in moderate or heavy drinking and 32 percent more likely to use street drugs. What's more, they were 37 percent more likely to attempt suicide.
It is not exactly surprising that children exposed to violence will go on to return the favor in adulthood, whether that is spanking their own children or hitting their partner. In a 2017 study, researchers interviewed 758 young adults and asked them how often they were spanked, slapped, or struck growing up as a physical form of punishment. They discovered that those that had were 29 percent more likely to commit violence when they were in a relationship. They were also more likely to be the receiver of violence. But it's not just romantic relationships – a meta-analysis of 36 studies on corporal punishment found that parents who spanked their child were three times as likely to report their children as having aggressive behavior later on.