Expressive crimes (e.g., rape) are committed for the sake of expected pleasure; instrumental crimes (e.g., burglary) mainly for the sake of expected gain. Both often can be deterred by disincentives -- the fear of pain the threat of punishment. To the criminal, the cost of a crime is the risk of punishment. Not what is threatened by the law, but the punishment he risks given his actual chances of being convicted and imprisoned
At present the actual punishment is much lower: 6 to 7 days per burglary, roughly 2 years per murder, 6 months per rape, 2 months per robbery; aggravated assault costs 8 to 9 days; car theft 2 to 3 days. These risks still deter many prospective criminals, but are too low to reduce the crime rate. Most people are not aware of how small the actual chance of punishment is; but professional criminals are. It is what makes the career attractive. They know that on average they will serve no more than 40 per cent of their sentence, and that most of them will not serve at all--they are rarely caught.
Some people become criminals because small offenses are not dealt with effectively. In our childhood, most humans learn that there are social limits to their natural aggression. While some are inherently more aggressive than others, virtually all humans have a potential for becoming aggressive. This is due to a rich genetic past which favored aggression in early humans. Humans still have the remnants of a reptilian brain that told its host, "kill, eat, reproduce."
Family structures and functioning have crucial impacts on socialization, the capacity for symbolic interaction, self-concepts. Families are primary agents of socialization are tempting to consider as direct causal agents of crime. All except a handful of jurisdictions recognize the immediacy of this connection in "contributing to delinquency" statutes, parental liability laws, and a number of other restitution schemes. Many criminological theories (social disorganization, social learning, and especially social control) grant the family causal significance. It has been demonstrated statistically significant causal relationships between family contexts and both juvenile and adult crime.
Seven family conditions are considered: parental imprisonment, divorce, stepfamilies, adoption, punitive parenting, incompetent parenting, and single parenting. The first four come primarily from what is called the "broken home". Punitive and incompetent parenting have been taken from the literature on dysfunctional families, which are in fact "functionally broken". Single parenting refers to unwed mothering, either by misfortune or choice, the latter not qualifying as either broken or dysfunctional but deviating from the cultural standard of nuclear family structure. Six behavioral outcomes are considered: property crime, violent crime, mental disorder, alcoholism, drug addiction, and status offenses.
Through a combination of bad parenting, institutional failure and the weakness of people they learn to exploit, some children grow up learning they can get away with aggressive actions. When they commit offenses that are serious enough for police, courts and social workers to deal with, it is often too late - a cumulative pattern of successful aggression is already established.
Some causes are uncontrollable, for e.g. the age of the population: the more young males, the more