Does Criminal Law Deter? A Behavioral Science Investigation

Does criminal law deter? Given available behavioral science data, the short answer is: generally, no. Having a criminal justice system that imposes liability and punishment for violations deters.1 Allocation of police resources or the use of enforcement methods that dramatically increase the capture rate can deter. But criminal law the substantive rules governing the distribution of criminal liability and punishment does not materially effect deterrence, we will argue, contrary to what law- and policy-makers have assumed for decades. Our claim is not that criminal law formulation can never influence behavior but rather that the conditions under which it can do so are not typical. By contrast, criminal law makers and adjudicators formulate and apply criminal law rules on the assumption that they nearly always influence conduct. And it is that working assumption that we find so disturbing and so dangerous. Our skepticism of criminal law's deterrent effect is derived in large part from a behavioral science research critique of the alleged path of influence from doctrine to behavioral response. That critique finds that the transmission of influence faces so many hurdles and is so unlikely to clear them all that it will be the unusual instance in which the doctrine can ultimately influence conduct. Yet this is a startling conclusion because it contradicts the common wisdom and standard practice of law makers and scholars. If, as appears to be the case, doctrinal formulation does not affect conduct, then most of the criminal analysis of the past forty years has been misguided. Where doctrine has been formulated to maximize deterrence, overriding other goals, such as doing justice, such deterrence analysis has frustrated those other goals for no apparent benefit. Let us briefly sketch our line of argument: The behavioral sciences increasingly call into question the assumption of criminal law's ex ante influence on conduct. Potential offenders commonly do not know the legal rules, either directly or indirectly, even those rules that have been explicitly formulated to produce a behavioral effect. Even if they know the rules, the cost-benefit analysis potential offenders perceive which is the only cost-benefit analysis that matters commonly leads to a conclusion suggesting violation rather than compliance, either because the perceived likelihood of punishment is so small, or because it is so distant as to be highly discounted, or for a variety of other or a combination of reasons. And, even if they know the legal rules and perceive a cost-benefit analysis that urges compliance, potential offenders commonly cannot or will not bring such knowledge to bear to guide their conduct in their own best interests, such failure stemming from a variety of social, situational, or chemical influences. Even if no one of these three hurdles is fatal to law's behavioral influence, their cumulative effect typically is. Part I reviews the behavioral science evidence. But some might argue that, although a behavioral science analysis of criminal law's action path says doctrinal formulation can rarely influence conduct, it might in fact 3 do so in some mysterious way presently beyond the understanding of human knowledge. We can test this argument by looking at the effect of specific doctrinal formulations on the crime rates they are intended to lower. The available studies of what one might call 'aggregated effects' -- that is, studies that do not concern themselves with how a deterrent effect might come about but look strictly to whether an effect of doctrine on crime rate can be found -- seem consistent with our conclusion above. A majority of these studies find no discernible deterrent effect of doctrinal formulation, which does not surprise us. But others claim to find such an effect and we must explain these results. Even if the mechanism of transmission from doctrinal formulation to behavioral influence is unknown, the finding of such a connection may be inconsistent with some of our claims and must be dealt with, especially since many deterrence advocates will speculate that the causal mechanism in the 'black box' is deterrence. We find that some of the aggregated-effect studies are simply poorly done and cannot reliably support a conclusion that doctrine affects crime rates. Others seem undeniably to have found an effect on crime rate, but we suspect that much if not most of this is the result of incapacitative rather than deterrent effects. Increasing prison terms, for example, could be taken as providing a greater deterrent threat, but a resulting reduction in crime may be the result of the isolating effect of longer incarcerations rather than their deterrent effect. But even if one concludes that some of these studies show a deterrent effect from doctrinal formulation, which we do, the specific circumstances of those studies serve generally to affirm our points about the prerequisites of deterrence. That is, these studies involve rules and target audiences that do what is rarely done: to satisfy the prerequisites to deterrence. The circumstances of these studies only serve to illustrate that the existence of such prerequisites are not typical. Part II reviews these aggregated effect studies.