To the legal system, the answer is clear: children have the requisite moral sense--the ability to tell right from wrong--by age 7 to 15, depending on which state they live in, and so can be held responsible for their actions. The Roman Catholic Church pegs it at the early end of that range: children reach the "age of reason" by the tender age of 7, a milestone marked by their first confession of sin and holy communion. Developmental psychologists and other researchers who study the question are not so sure. How old a child must be to both know in his mind and feel in his heart that lying, stealing, cheating, hurting--let alone murdering--are morally wrong is a matter of scientific debate.
But the question of when is not nearly so fraught as the question of how. Although they pretty much agree that living in a crack house--with people who respond to challenges with violence, and bereft of parental love, supervision and models of moral behavior--can leave a child's conscience stillborn, scientists are struggling toward a definitive answer to the question of how children develop a sense of right and wrong. "If there is any consensus, it is that conscience is a combination of head, heart and hand," says Marvin Berkowitz, professor of character development at the University of Missouri, St. Louis. "It is knowing the good, loving the good and doing the good. And that requires both cognitive and emotional components."
The emotional piece falls into place first. "All children are born with a running start on the path to moral development," says psychologist William Damon of Stanford University. The reason is that empathy, the key emotion supporting a sense of right and wrong, emerges early and, it seems, naturally. Babies cry in response to the wails of other babies, "and not just because it's a sound that upsets them," notes Carolyn Zahn-Waxler of the National Institute of Mental Health. "They cry more in response to human cries than to other aversive sounds. Somehow, there's a built-in capacity to respond to the needs of others." Babies as young as 1 try to console others in distress. Toddlers offer their security blanket to a teary-eyed parent or a favorite toy to a distraught sibling, as if understanding that the very object that brings them comfort will do the same to another.
Although there seems to be some heritable component to empathy--identical twins, who have identical genes, show more similarity in their response to others' distress than fraternal twins do--it can be twisted, warped or crushed like a fragile sprout. Empathy means, at heart, the ability to respond to another's distress in a way more appropriate to her situation than to your own. "The development of empathy has a lot to do with how children experience emotions and how people respond to their emotional states," argues Berkowitz. "It's not automatic." If a child's sadness is met with stony silence rather than a hug, if her loneliness is met with continued abandonment, then she is in danger of losing her natural empathy. Kids who, as 14-month-olds, exhibit high levels of empathy typically become less empathetic after only six months if they live in homes filled with conflict, and if they seldom feel a mother's love, finds Zahn-Waxler.
The other emotional ingredients of conscience are that quaint pair, guilt and shame. Although some child advocates insist that no child should ever be shamed, scientists who study moral development disagree. "Guilt and shame are part of conscience," says Berkowitz. In young children, the sense of right and wrong is born of the feeling that you have disappointed someone you love, usually your parents. If there is no one whose love you need, whose disapproval breaks your heart, you are missing a crucial source of the emotions that add up to knowing right from wrong and acting on it.
Important as emotions are in the development of conscience, the heart can falter without the head. The very thought of shooting a little girl inspires in most people a profound feeling of horror. But feelings can fail us when we face more ambiguous moral choices, such as whether it is right to help a struggling friend cheat on a test. Much as children pass through stages of cognitive reasoning, so they pass through six stages of moral reasoning. In the model developed by the late Lawrence Kohlberg and still accepted today, children's first glimmer of conscience comes in the form of thinking, "I won't do this; Mommy will punish me if I do." That gives way to a positive spin: "I won't do this bad thing, because I want a reward for being good." Both forms of reasoning at this early stage, which roughly coincides with toddlerhood, turn on self-interest. But most preschoolers also grasp and believe in abstract ideas like fairness and reciprocity. When asked, as part of an experiment, how to distribute a pile of toys or a box of cookies to a group of children, many respond with explanations such as "We should all get the same," reports Stanford's Damon.
Also in the early years, roughly until 6 or 7, "most children make moral judgments on the basis of the damage done," says David Elkind, professor of child development at Tufts University. They condemn the child who broke three glasses while helping Mom load the dishwasher more than the child who broke one glass while playing with the good crystal. But after the age of 7 or 8, children begin to make judgments based on intent: they know that smashing the Waterford while using it as a Barbie pool will land them in more trouble than shattering an entire place setting while clearing the table.
By middle childhood, if all goes well, children begin to seek social approval. This shows up as "I won't do this because I want people to like me," and then "I won't do this because it is against the law." By 8, children generally understand that retaliation is wrong, and their brain's so-called judgment circuit, centered in the prefrontal cortex, approaches maturity. In the final stage, one that even many adults fall short of, abstract ideals guide moral reasoning. Ideally, the adolescent recognizes a social contract ("I won't do it because I am obliged not to") and something like universal rights ("I won't do this because it is simply wrong").
The age at which a child reaches these milestones of moral reasoning varies with how he is raised and how those around him act. Unlike empathy, full-fledged conscience does not seem innate. Children acquire the cognitive understanding of right and wrong by observing the behavior of the people most important to them, usually (and hopefully) their parents. If Dad reacts to injured pride--"He dissed me!"--with violence, that becomes the model for his son. And that is only the beginning of a parent's influence.
Different styles of parenting seem to nourish, or beat down, a child's nascent conscience. Both autocratic and permissive parenting, although they seem like opposites, tend to shape the same behavior and attitudes in children. Children of permissive parents often struggle to learn the limits of acceptable behavior. They typically develop poor self-control, perhaps because anything-goes parenting conveys the message that none is needed. Autocratic parenting says that the course of control is outside the child--namely, parents--so there is no need to develop an inner moral compass.
Sitting in the sensible middle is "authoritative" parenting that, say numerous studies, nurtures a child's respect for rules. Authoritative means setting firm limits, letting your child know your views of right and wrong, but "explaining instead of forcing," says Berkowitz. Authoritative falls short of the "do it because I say so!" autocratic school of parenting. For that reason, many cultural conservatives blame authoritative parenting for everything from kids who kill to gangsta rap, but authoritative does not mean permissive. It does not mean negotiating over whether a 12-year-old can leave the house at 9 p.m. clutching a six-pack. And it does not mean trying to lay out the fine points of retributive justice to a 2-year-old who just shoved the playmate who "pushed me first!" But parents who explain their moral reasoning provide a model their child can emulate. "If you want a kid who respects and cares about others," says Berkowitz, "you have to first give him respect and show that you care about him."
The community, too, shapes a child's conscience. It will come as no surprise to parents that children have built-in hypocrisy detectors. ("But Mommy, if it's wrong to lie, why did you tell her she looked beautiful?") If the football coach preaches winning above all, and if Mom lies to get her child excused from class in order to take another day of vacation, and if Dad reams out a teacher who reprimanded his daughter for cheating, "children learn not to take moral messages seriously," says Damon.
Heart and head will take a child only so far, however. "I suspect that if you sat down [the first-grade shooter] when he was quiet and calm, before this happened, and asked, 'Is it bad to shoot someone?' he would have said yes," says psychologist Laurence Steinberg of Temple University and director of a MacArthur Foundation program on juvenile justice. How much he understood about the consequences of shooting and the finality of death is unknown. But choosing not to undertake a horrific act requires the third ingredient of conscience: a gut-wrenching aversion to wrong. "Gut-wrenching" is not merely a figure of speech: it means the racing heart, sweaty palms and churning stomach that moral individuals would feel if forced to, say, burglarize a house. Some people simply lack this stress response, but probably not because of a genetic defect. When Adrian Raine of the University of Southern California recorded how 15-year-olds' heart rates, EEGs (a measure of brain activity) and other factors changed in response to stress, he found some cool customers who were not fazed by anything. Compared with kids with a normal stress response, they had a greater chance of being criminals at the age of 24. Perhaps low arousability makes kids seek out excitement and danger, Raine suggests. Or maybe it makes them fearless. "Kids who come from a bad home environment, who are battered from pillar to post, may become inoculated to stress," says Raine. "Their nervous system may simply not be wired to ring a warning bell" when they are about to do something dangerous--or wrong. This brain wiring may be what's missing in kids who "know" right from wrong but fail to act on it.
When do the heart, the head and the gut come together to produce, if not a moral philosopher, at least a moral child? "My hunch is that it's probably not complete until a child is close to 12," says Steinberg. "But a lot of these things are still developing at 15." And sometimes, as any glance at the headlines will tell you, they fail to develop at all.