Despite years of research casting doubt on its impact, state-approved physical punishment continues—especially for vulnerable students.

Millions of students across the country began a new grade this fall. But for eight-year-old Ana, joining a traditional second-grade class is an especially big milestone. At five years old, Ana was diagnosed with autism, intermittent explosive disorder, and attention-deficit/hyperactivity disorder (ADHD). Before this school year, she was always placed in special education.

Ana struggled in class as soon as she started preschool in Oklahoma, so her mother, Jane, decided to put her in developmental pre-K. (The names of Ana—who remains in the school system described in this story—and her mother have been changed.) But in that environment, Ana was often called out for behavior that stemmed from her symptoms, and teachers told her mother she would do better with regular discipline. So her mom gave the school permission to use corporal punishment.

"They spanked me at the teacher's desk with a hard wooden paddle that looked like a snowshoe. I was scared, and it felt bad, so I cried and yelled, but then I had to go [back to the activity I was doing]," Ana recalls. "I got spanked a lot. That's all I can say, because I can't remember how many times." For the next few years, Ana was spanked and paddled.

These actions, and other forms of physical discipline imposed on students, are widely known as corporal punishment, though there is no comprehensive federal definition of the term. In late 2016, the secretary of education under President Barack Obama, John King, issued a letter against the practice, which he described as "personnel intentionally inflicting pain on a child as a punishment or in an attempt to change the child's behavior." Ultimately he was making this plea to states, which have the final say on whether corporal punishment is used.

Fifteen states expressly permit corporal punishment in public schools, King noted; seven more states allow the practice by having no laws against it, and most allow it in private schools. Under that patchwork of policy, an Education Week analysis found, more than 109,000 students were physically punished in 21 states during the 2013–14 school year. Decades of research suggest that those students are at least as likely to experience negative effects from this punishment—including mental-health and behavioral problems—as positive ones.

"Corporal punishment can be traumatizing to a child," says Mojdeh Bayat, a professor of early childhood education at DePaul University. The degree of trauma and its long-term effects, she adds, vary by the child's psychological and developmental capacities—which present unique challenges among the students most likely to be physically punished. Corporal punishment is used disproportionately on certain students: more often on boys than girls, and frequently on individuals with disabilities and children of color, groups that typically have lower-quality educational options than their peers to begin with.

In states still using corporal punishment, students with disabilities can be up to five times more likely to experience corporal punishment than students without disabilities, the Society for Research in Child Development reported in 2016. And while white students in Kentucky are about seven times more likely to attend to school that uses corporal punishment, black students are substantially more likely to receive it.

In his letter, King wrote that such disparities "shock the conscience." State senators in Tennessee were so disturbed by evidence of disproportionate physical discipline for students with disabilities that they urged the comptroller to investigate the trend, particularly why it might be happening.

Ana's mom believes that her daughter's own disabilities led to school staff viewing her as a "problem child," a perception that can also drive harsher punishment for black students, according to Bayat. "Negative treatment of black students has its roots in a much bigger problem of discriminatory perceptions, attitudes, and behaviors toward black students," she says.

Epiphani Ali felt singled out as a black student for corporal punishment early on, in Ohio. "When I was six years old I attended a private Catholic school, where the teachers used paddles," Ali says. "It made me feel like I was being abused for no good reason—I have been on the honor roll and in honors classes since my induction into the schooling system." She noticed that the few black students in her class seemed like the one ones chosen for this form of discipline. Although it didn't affect her performance in school, she says, she resented it.

Racial discrepancies in punishment also vary starkly by location. Black children in more than half of Alabama and Mississippi school districts are 51 percent more likely than their white peers to experience corporal punishment, the SRCD report found. But in one-fifth of those state's districts, black children are five times more likely to receive corporal punishment.

In fact, research suggests that location is the key factor in predicting schools' use of physical discipline. In a Children and Youth Services Review study published last year, researchers analyzed data from the Department of Education and found that the number of Southern-born students in a public school was more closely linked to the use of corporal punishment than any other factor. The second most reliable predictor was the local average education level; the less educated a school's surrounding county, the more likely it was to use physical discipline.

"Southernness and rurality here reflect the cultural aspects rather than the geographical definition of a county and may indicate the probability that a school in that area will use [this type of discipline]," said Sarah Font, an assistant professor of sociology at Pennsylvania State University and paper co-author, in a Penn State news release. "Southern and rural cultures have been described as emphasizing tradition and order, and are more conservative in their religious and political affiliations."

Jane believes these values informed the use of physical discipline at Ana's school in Oklahoma. "I don't think the teachers who spanked her knew how to address her needs appropriately, so they fell back on what was culturally sanctioned in our rural, conservative, part of the country," she says.

Per Font's study, children who are likely to be exposed to corporal punishment in schools are also more likely to see that kind of punishment at home. For such students, the researchers write, "It may be the case that neither home nor school provides an environment free from the threat of violence."

When it comes to spanking at home, at least, a majority of American parents still support it. A 2016 Gallup poll found that 64 percent of adults in the United States approve of "spanking children." Students themselves sometimes choose physical punishment over suspension or other disciplinary alternatives, with approval from their parents, many of whom believe it results in instant correction of undesired behavior.

Research indicates that can be the case—but with the risk of long-term costs for the child's mental health. A 2002 paper surveying 88 studies from across 62 years of research found that physical discipline from parents did get children to immediately stop misbehaving. But the paper's author, Elizabeth Gershoff—who co-authored the 2017 study with Font—also found corporal punishment to be linked to higher aggression, decreased learning of morals, and lower mental health over time.

A little over a decade of study later, Gershoff concluded that "spanking is a form of violence against children that should no longer be a part of American childrearing." The American Psychological Association declared the same for school-sanctioned spanking as early as 1975, approving a resolution that year opposing the practice in schools and other institutions. The resolution claimed corporal punishment is not an effective long-term deterrent of negative classroom behaviors unless it's precisely controlled for "timing, duration, intensity, and specificity," and said it "is likely to train students to use physical violence to control behavior."

More recent research has pointed toward other negative long-term effects, including, in response to severe physical punishment, symptoms in line with post-traumatic stress disorder: frequent memories or discussion of the incidents, loss of interest in activities, difficulty concentrating, and anxiety. Regular use of the practice has also been associated with increased rates of antisocial behavior, achievement issues, and a damaged sense of self.

Kristen Tucker, who has been diagnosed with ADHD, has noticed that, even as an adult, she harshly scrutinizes herself, which she believes comes from being physically disciplined attending schools in Alaska and later, Arkansas. "I constantly apologize even when I shouldn't," she says. "I get very scared and uncomfortable when I know there will be a review of my work, and I feel like it makes it hard for me to keep mainstream work, where others are in charge of me."

Boyat points out that, even as corporal punishment continues in schools, it's been essentially eliminated elsewhere—in our prison system. "If corporal punishment is implemented on our prison population and criminals in the United States, it will be a 'cruel and unusual punishment.' Why do we not consider our children worthy of the same rights as our current prisoners?"

But policies that deal, in effect, with childrearing can be hard to legislate. Unlike other, legally regulated forms of violence, spanking and other acts of physical discipline are often seen as legitimate options for parents and teachers. Some administrators are pushing back, as in the Greenville public school district in Mississippi—the state where corporal punishment is most common—that voted against physical discipline in late January. But most parents and teachers in the district still reportedly support the use of spanking and paddling, at their discretion.

For Ali, when adults used corporal punishment to assert their power, it dealt a blow to her own. "I felt worthless, powerless, and voiceless," she says. "Being a child and not having someone stand up for you is very detrimental to your psyche."