Causation, Contribution, and Legal Liability: An Empirical Study
Solan, Lawrence M., Darley, John M., Law and Contemporary Problems
LAWRENCE M. SOLAN [*]
JOHN M. DARLEY [**]
This article presents empirical evidence of the ways people compare judgments of liability with judgments of causation and contribution. Specifically, the article reports the results of experiments designed to show whether people regard causation and enablement as necessary elements of liability. As suggested by past psychological research, the experiments also test what roles other factors, such as the defendant's state of mind and the severity of the victim's injury, play in people's judgments of both causation and liability.
The experiments ask people for their judgments concerning types of cases that the law does not treat uniformly. In one type of case, the defendant has left his keys in the ignition of his car. Someone steals the car and gets into an accident. In the other type, a social host sends an intoxicated guest out in a car to drive another guest home and the guest gets into an accident. Both of these scenarios illustrate what Robert Rabin has called "enabling torts."  The defendant does not directly cause the harm but sets the stage for the individual who does. As discussed below, courts disagree not only as to whether such cases should generate liability for the enabler, but also as to how these cases should be conceptualized in causal terms.
The results of the experiment show no more uniformity of judgment than the case law. Some respondents thought that there should be liability for the enabler, while others disagreed. Nonetheless, the study casts light on some important contemporary debates in the law of torts. First, the results begin to offer an explanation for the disagreement in the case law. Courts do not use the expression enabling torts"; rather, they decide these cases using traditional tort concepts, such as duty, foreseeability, and proximate causation.  For example, some courts deny recovery for lack of proximate causation. Others allow recovery on the basis of proximate causation. Still others talk, instead, of duty. Professor Rabin's approach suggests an additional possibility: To the extent that people distinguish between causation and enablement, there may be no cause in fact in these cases. However, because enablement, like actual causation, is a "but for" relationship, legal thinkers who draw the distinction will find it di fficult to articulate the problem in that way within the taxonomy of conventional tort theory. This article explores the possibility of such alternative conceptualizations.
The results of the study show people to be divided as to how they conceptualize these cases. Many respondents appear content to group causation and enablement together and to regard them essentially as components of a general concept of contribution. Those who do distinguish between the two disagree as to whether enablement is an adequate basis to establish liability. Some who see the actor as an enabler but not a cause do not assign liability to the actor, while others who see him only as enabling do assign liability. Thus, the uncertainty expressed by the courts perhaps mirrors the difficulty that ordinary language users have with these problems.
Second, the experiments strongly suggest that people believe that the amount of harm for which a defendant should be held liable depends on the extent of the defendant's contribution to bringing about the harm. In other words, people's naive sense of justice comports with theories of proportional liability.
Third, the actor's state of mind predicts liability to some extent, even when the law does not make such distinctions. For example, a willful enabler is typically assigned more liability than is a reckless one.
Part II of this article presents a brief outline of the current state of the law concerning cases that can be characterized as enabling torts. The discussion is not intended to be exhaustive. …