in New York for a five-year crime spree in which the defendants allegedly impersonated police to take drugs and cash from large-scale cocaine dealers. The crimes occurred across five states and netted more than $20 million worth of cocaine and $4 million in cash. More than 100 cocaine dealers were victimized.

      According to court papers, the robbers sometimes conducted police-style traffic stops of cocaine dealers who were transporting drugs or money. In other cases, the robbers invaded cocaine dealers’ homes and bound family members with duct tape and handcuffs, sometimes holding them hostage for days. One victim recounted how the robbers applied pliers to his testicles and threatened to squeeze if he didn’t reveal the location of large caches of cocaine. Other victims reported being tortured, including having their heads held under water to force them to talk. After the cocaine was located, the gang sold the drugs on the streets of New York.

At the opposite end of the spectrum from physical abuse, some parents may not discipline their kids at all. If a child is never reigned in after misbehaving, he may be less likely to learn proper boundaries or decision-making skills. Later in life, that kid may be less able to conform to society’s rules, including laws against violence. (In Chapter 11, I discuss in more detail the causes of all crime.)

      Suffering from mental problems

      Studies of groups of murderers have revealed that murderers are likely to have lower IQs than the average citizen. You might say that they have mental deficiencies.

      Note that a mental deficiency is much different from a mental disease, which is a mental illness as defined by psychiatrists and psychologists. In court, a mental disease can be the basis of an insanity defense. A mental deficiency such as a decreased IQ, on the other hand, can’t be part of an insanity defense; it simply helps explain, in part, why someone may have committed an act of violence.

      One mental disease that prosecutors often encounter in criminal cases is paranoid schizophrenia. For example, a person who suffers from paranoid schizophrenia may experience a delusion in which he believes his television is telling him to kill his neighbor’s dog. If he actually kills the dog, he’ll likely be excused from criminal responsibility because of an insanity defense. (For a more detailed discussion of the insanity defense, see Chapter 20.)

      A personality disorder is yet another mental problem that can be a cause of violence. Like a mental disease, a personality disorder is diagnosed by a psychologist or psychiatrist. But it’s not considered as severe a disability as a mental disease and, therefore, can’t be used for an insanity defense. These are the two best-known personality disorders in the criminal justice system:

       Narcissistic personality disorder: Someone with this disorder generally sees herself as very important, needs others to see her as important, and lacks the ability to experience empathy with others.

       Antisocial personality disorder: Someone with this disorder has a pattern of disregarding the rights of others that starts when she’s a juvenile and progresses into adulthood.

Similar to antisocial personality disorder is a characteristic known as psychopathy. A psychopath is a predator who uses charm, manipulation, and violence to control others and achieve her own selfish needs without experiencing any guilt or remorse. Studies of psychopaths within prisons reveal that psychopaths are generally untreatable and may even become more cunning and manipulative after being subjected to treatment. Psychopaths are also considered much more likely to engage in future acts of violence than other inmates.

      See Chapter 14 for a more detailed discussion of how a psychological or personality disorder can lead to criminal behavior.

      Being influenced by society

      Some criminologists look to cultural values within a society as a potential cause for violence. For example, the murder rate in Japan has been measured at less than 10 percent of that in the United States. For this reason, some people have theorized that the United States, which highly values independence and self-reliance, may have more violence, in part, because of these values. In contrast, Japan is a more socially organized country that places less value on independently resolving conflict and, thus, has less violence.

      Today’s society also offers people constant access to violent messages. Some people believe that relentless exposure to violence (through TV programs, movies, music, video games, and so on) may desensitize children, making them more likely to resort to violence to resolve conflicts. One analysis concluded that by the time the average child in the United States reaches the age of 8, she has seen 8,000 murders on TV, and by the time she reaches 18, she’s seen more than 200,000 acts of violence on TV.

      I devote Chapter 13 to exploring theories of how society may influence someone to become a criminal.

      Making a personal choice

      Drugs, mental health, and pop culture all may play a role in influencing someone to commit a violent crime, as I discuss earlier in the chapter. But another possibility is that criminal violence is, in part, a conscious, rational choice based on how an individual weighs the risks of committing a crime versus its potential rewards.

      How else can you explain why two brothers raised in the same family environment and culture take radically different paths in life? Why does one commit capital murder while the other becomes a productive member of society? (I explore this question in detail in Chapter 12.)