In a lawsuit where the claim is that a product or substance caused a disease or injury, one would think that a sine qua non of the plaintiff's case is strong evidence that the product or substance is more likely than not the cause of the particular injury the plaintiff claims to have. Yet, my observation of these cases over many years is that while defense lawyers may firmly believe that such evidence is weak, lacking, or bogus, the plaintiff is often still able to make substantial recoveries before juries.



Defense lawyers frequently express frustration with juries that seem to ignore the powerful scientific evidence they present to counter the plaintiff's claims. They characterize the jury as unsophisticated, easily manipulated, and led by emotions rather than thought. In this article we will examine why jurors so often reject the defense's strong scientific case and ways that the defense might overcome that problem.

In what follows I want you to make an assumption: That the defense's scientific case on causation is strong and the plaintiff's is relatively weak. We're not talking about the relationship between asbestos exposure and asbestosis. With that in mind, let us first understand why the plaintiff's case may be appealing to jurors despite its weakness.

First, defense lawyers need to understand that when they step outside their role as lawyers that most of them are not much different from everyone else. Acting as a defense lawyer entails thinking in a logical and rationality maximizing manner. The weakness of some defense lawyers is expecting jurors to think in the same way when, in their everyday lives, most of these same lawyers frequently do not think this way. Let's take some examples.

1. Would you choose to engage in an activity that could provide great rewards, but brought great misery when unsuccessful and which had a fifty percent failure rate? My guess is that many of you would not, yet almost all of you have chosen or will choose to get married, an activity with a fifty percent failure rate. Interestingly, many people (including defense lawyers) choose to marry knowing what the failure rate is. Despite this assumption of the risk, many still blame others for the failure. We find this external attribution of blame to be a common occurrence among jurors, even when the plaintiff has knowingly engaged in a well known and risky activity.

2. Bushes that burn that never burn; waters of a sea parted by the raising of a rod; a woman turned into a pillar of salt; another woman made pregnant by a God and giving birth to a God; and water turned into wine. People unfamiliar with the Judeo-Christian religious tradition might find these to be bizarre and impossible events. Despite no scientific evidence to support their actual occurrence, many millions of people believe them to have been real. Count among that group many defense lawyers who unquestionably have faith in their reality. I am not proposing that none of these events are false.

But if you think of common sense as like faith (a naturally felt belief in the way the world works in the absence of much empirical evidence), it is easy to see how difficult it might be to change common sense beliefs with scientific evidence. Some of these common sense beliefs are that just about anything has the ability to cause cancer; that exposure to any amount of a chemical can cause devastating injuries; and that single chemicals can cause multitudes of injuries. Is it really so hard to conceive of jurors being easily persuaded that exposure to welding fumes can cause Parkinson's disease and ignoring evidence that runs counter to that?

3. How many defense lawyers buy lottery tickets? Not all, I'm sure. But I'd also "wager" that many do. Some of these are the same lawyers that argue dose/response relationships to jurors and present them with risk assessments. These lawyers believe it is worth spending money for a less than one in several million chances to win the lottery, yet expect jurors to conclude that the one in a million chance of getting injured by a chemical exposure precludes the plaintiff from being that person.

When we add in superstition, habit, custom and tradition into the lives of defense lawyers we see that much of the thinking in which they engage in their every day lives is not commanded by the same logic and super rationality that commands their thinking in the courtroom. Most importantly, that type of thinking is clearly not what is required to negotiate the challenges of every day life. Non rational and illogical thinking patterns can be quite successful strategies in everyday life. They serve their purposes.

Conclusion

In everyday life, scientists and lawyers do not behave like scientists and lawyers. For jurors a trial is everyday life. They do not and will not reason like experts. To the lawyer and scientist, jurors may be making mistakes in their reasoning, but they are not. They are doing the reasoning of everyday life. How this is done with scientific evidence can be understood and consequently the evidence can be presented to them in a way that makes sense to everyone, lawyers, scientists, and jurors alike.