Deterrence

The narrow sense: fear of punishment. In a narrow sense, deterrence can be defined as the prevention of socially undesirable behavior by fear of punishment. A person who might otherwise have committed a crime is restrained by the thought of the unpleasant consequences of detection, trial, conviction, and sentence ("simple deterrence"). A distinction is often made between general deterrence, which signifies the deterrent effect of the threat of punishment, and special deterrence (or individual deterrence), which signifies the effect of actual punishment on the offender.

The basic phenomenon is the fear of punishment. This fear may be influenced by the experience of punishment. When an offender has been punished he knows what it is like to be prosecuted and punished, and this may strengthen his fear of the law. The experience may, however, work the other way. It is conceivable that the offender previously had exaggerated ideas of the consequences of being caught and now draws the conclusion that it was not as bad as he had imagined. In this case, the special deterrent effect of the punishment is negative. More important, probably, a person who has been convicted of a somewhat more serious crime, and especially one who was sentenced to imprisonment, will have less to fear from a new conviction, since his reputation is already tarnished. In practice, it will be difficult or impossible to isolate the deterrent effects of the prison experience from other effects of the stay in prison. What we can measure is how offenders perform after punishment, expressed in figures of recidivism.

The broad sense: the moral effects of criminal law. In a broad sense, deterrence is taken to include not only the effect of fear on the potential offender but also other influences produced by the threat and imposition of punishment. Criminal law is not only a price tariff but also an expression of society's disapproval of forbidden behavior, a fact influencing citizens in various ways. Most people have a certain respect for formal law as such. Moreover, the criminalization of a certain type of behavior may work as a moral eye-opener, making people realize the socially harmful character of the act ("the law as a teacher of right and wrong"). The moral condemnation expressed through the criminal law may also affect the moral attitudes of the individual in a less reflective way. Various labels are used to characterize these effects: the moral, the educative, the socializing, the attitude-shaping, or the norm-strengthening influence of the law. From the legislator's perspective, the creation of moral inhibitions is of greater value than mere deterrence, because the former may work even in situations in which a person need not fear detection and punishment. In the Scandinavian countries and Germany the moral component in general prevention is considered to be essential. For the moral effect of criminal law the perceived legitimacy of the system, rooted in the application of principles of justice, proportionality and fairness, are regarded as more important than severity of sentences.

General deterrence and general prevention. In continental literature general prevention is used as a technical term that denotes both the effect of fear and the moral effect of the criminal law. This is equivalent to general deterrence in the broad sense, but the term deterrence tends to focus on the effect of fear. Most American research papers on deterrence do not mention the question of definition but do in fact work with the broad concept, since they are concerned with all effects on crime rates of the system of criminal justice and make no effort to exclude effects produced through mechanisms other than fear.

Habituative effects of criminal law. Much law-abiding conduct is habitual, and the threat of punishment plays a role in this habit formation. It is sufficient to mention the response of drivers to traffic signals. In a broad sense deterrence can be taken to include also the habituative effects of the law. Habit formation is, however, a secondary phenomenon. For a habit to be established, there must first be compliance based on other sources, which may include fear and respect for the law. The habit is eventually formed through repetition of the law-abiding conduct.