The typical parent, when whacking a misbehaving child, doesn't pause to wonder: "What does science have to say about the efficacy of corporal punishment?" If they are thinking anything at all, it's: "Here comes justice!" And while the typical parent may not know or care, the science on corporal punishment of kids is pretty clear. Despite the rise of the timeout and other nonphysical forms of punishment, most American parents hit, pinch, shake, or otherwise lay violent hands on their youngsters: 63 percent of parents physically discipline their 1- to 2-year-olds, and 85 percent of adolescents have been physically punished by their parents. Parents cite children's aggression and failure to comply with a request as the most common reasons for hitting them.
The science also shows that corporal punishment is like smoking: It's a rare human being who can refrain from stepping up from a mild, relatively harmless dose to an excessive and harmful one. Three cigarettes a month won't hurt you much, and a little smack on the behind once a month won't harm your child. But who smokes three cigarettes a month? To call corporal punishment addictive would be imprecise, but there's a strong natural tendency to escalate the frequency and severity of punishment. More than one-third of all parents who start out with relatively mild punishments end up crossing the line drawn by the state to define child abuse: hitting with an object, harsh and cruel hitting, and so on. Children, endowed with wonderful flexibility and ability to learn, typically adapt to punishment faster than parents can escalate it, which helps encourage a little hitting to lead to a lot of hitting. And, like frequent smoking, frequent corporal punishment has serious, well-proven bad effects.
The negative effects on children include increased aggression and noncompliance—the very misbehaviors that most often inspire parents to hit in the first place—as well as poor academic achievement, poor quality of parent-child relationships, and increased risk of a mental-health problem (depression or anxiety, for instance). High levels of corporal punishment are also associated with problems that crop up later in life, including diminished ability to control one's impulses and poor physical-health outcomes (cancer, heart disease, chronic respiratory disease). Plus, there's the effect of increasing parents' aggression, and don't forget the consistent finding that physical punishment is a weak strategy for permanently changing behavior.
But parents keep on hitting. Why? The key is corporal punishment's temporary effectiveness in stopping a behavior. It does work—for a moment, anyway. The direct experience of that momentary pause in misbehavior has a powerful effect, conditioning the parent to hit again next time to achieve that jolt of fleeting success and blinding the parent to the long-term failure of hitting to improve behavior. The research consistently shows that the unwanted behavior will return at the same rate as before. But parents believe that corporal punishment works, and they are further encouraged in that belief by feeling that they have a right and even a duty to punish as harshly as necessary.
Part of the problem is that most of us pay, at best, selective attention to science—and scientists, for their part, have not done a good job of publicizing what they know about corporal punishment. Studies of parents have demonstrated that if they are predisposed not to see a problem in the way they rear their children, then they tend to dismiss any scientific finding suggesting that this presumed nonproblem is, in fact, a problem. In other words, if parents believe that hitting is an effective way to control children's behavior, and especially if that conviction is backed up by a strong moral, religious, or other cultural rationale for corporal punishment, they will confidently throw out any scientific findings that don't comport with their sense of their own experience.
The catch is that we frequently misperceive our own experience. Studies of parents' perceptions of child rearing, in particular, show that memory is an extremely unreliable guide in judging the efficacy of punishment. Those who believe in corporal punishment tend to remember that hitting a child worked: She talked back to me, I slapped her face, she shut her mouth. But they tend to forget that, after the brief pause brought on by having her face slapped, the child talked back again, and the talking back grew nastier and more frequent over time as the slaps grew harder.
So what's the case for not hitting? It can be argued from the science: Physical discipline doesn't work over the long run, it has bad side effects, and mild punishment often becomes more severe over time. Opponents of corporal punishment also advance moral and legal arguments. If you hit another adult you can be arrested and sued, after all, so shouldn't our smallest, weakest citizens have a right to equal or even more-than-equal protection under the law? In this country, if you do the same thing to your dog that you do to your child, you're more likely to get in trouble for mistreating the dog.