By: Dr. Ken Broda-Bahm -
In his recent State of the Union address, President Obama followed the common pattern of giving attention and applause lines to nearly every issue on the national agenda. But there was one issue that received no mention at all: climate change. The absence, noted by many commentators, extended even to areas where it would have been natural to mention the environment. The President's "clean energy" initiative, for example, was touted based on its ability to create jobs and bolster competitiveness, rather than its ability to help the environment.
This decision was no doubt the result of polling showing the American public is very skeptical of the science behind global warming. Recent surveys, for example, showing that nearly half of all Americans consider the threat of global warming to be "greatly exaggerated," likely contributed to advisers' view that the best overt reason to protect the environment is...to put America back to work. Despite a recorded 97-98% consensus within the scientific community, a large proportion of the citizenry simply doesn't believe the science behind climate change. This skepticism, however, isn't a passing political phenomenon, but is instead part of an observed tendency on the part of many to take scientific conclusions with more than a few grains of salt. Some individuals, including members of your jury, will elevate personal beliefs and experiences over scientific conclusions, no matter how well those conclusions are supported. This skepticism, explored in some recent research conducted by our group and others, has some important implications for expert witnesses looking for the best ways to convey scientific conclusions to their jury.
A recent New York Times piece asked the question of whether we are "hard-wired" to doubt science, drawing from the work of David Ropiek. The Harvard instructor notes in a recent book on risk assessment, that when science runs counter to something we take to be an instinctive belief or an established habit, our brain is setup to reject the new information. That is why people can steadfastly maintain that chemicals can harm us in even infintesimal amounts, or driving one's car won't harm the planet, even in the face of scientific evidence to the contrary.
These forms of skepticism can be seen in trial as well. As we have written recently, we conducted an on-line study focusing on the reactions of 3,718 participants who viewed summary arguments on both sides of a products liability case involving an injury caused by a ball coming off an aluminum alloy baseball bat. The plaintiff charged that the company made the injury more likely by shifting weight to the handle of the bat, allowing for a faster swing. From the defense, our study participants heard an expert explanation this change would not result in a higher batted-ball speed, because when you take a fixed weight bat, and simply shift weight to the handle, any gains in swing speed will be offset by a loss of mass at the hitting surface, and the net result is no measurable change in ball speed. The explanation was accurate from a physics standpoint, but many of our mock jurors simply could not accept that a higher swing speed would not result in a higher ball speed, no matter what the science says. As many noted, "if the weight of the bat is not an issue, why alter it?"
While many jurors can be skeptical of such explanations, we also know that scientific evidence is often very persuasive to jurors, particularly in criminal cases. So what determines which jurors will embrace science and which jurors will reject it? According to one recent study conducted by a Michigan Chief Judge (Shelton, 2010), the answer isn’t the so-called ‘CSI Effect,’ as jurors’ TV viewing preference for technology-oriented legal dramas had no independent effect on verdicts. Instead, the authors found that high expectations for scientific explanations tended to be based on the jurors’ own use of technology: Those using the latest smart-phone electronics, tended to expect the parties to make use of the latest science as well.
So, in addition to suggesting that it helps to keep an eye on what the venire members are typing and talking into before they come into court, what does this mean for the expert witness testifying in trial? Let me suggest three lessons:
1. Build a bridge from current knowledge. Scientists like to present new knowledge in a revolutionary framework ("this changes everything"), but human learning tends to be more evolutionary. In other words, instead of offering scientific evidence as a challenge to current beliefs, offer it as a supplement. For example, in the baseball physics situation discussed above, it would be less effective for the expert to offer his testimony as a refutation of the intuition that a faster swing will result in a faster hit, and more effective to offer that testimony as a confirmation of the intuition that a 32 ounce bat will deliver about the same amount of force to the ball, no matter where you put the weight.
2. Teach like you're on The Discovery Channel. As we've written in the past, experts should be teachers first, and persuaders second. Effective science-based expert testimony should engage the jury on the assumption that the individual jurors are smart, motivated, but as-yet uniformed students. Use stories to place the information in context, and demonstrations to make it real and memorable. Most importantly, use engaging visuals so jurors can both see and hear what you are talking about.
3. The most complete explanation wins. When it is a matter of one scientific expert versus another, resist the temptation to compare based on the time-honored tools of the academy. Jurors don't tend to be particularly impressed with credentials, and can miss the nuance in differences between methodologies. Instead, jurors will prefer the most complete explanation, and will discount any explanation that leaves some data unexamined and some questions unanswered. Also, as much as the idea can be an anathema to scientists, it also matters whose explanation is made to jibe most closely with common sense.
At the end of the day, while you can't count on jurors respecting science because it is science, you can rely on jurors accepting the message that makes the most sense.
William R. L. Anderegga, James W. Prallb, Jacob Haroldc, and Stephen H. Schneidera (2010). Expert credibility in climate change Proceedings of the National Academy of Sciences of the United States of America
Ropiek, D. (2010). How Risky is it Really McGraw-Hill
Shelton, D. E. (2010). Juror Expectations for Scientific Evidence in Criminal Cases: Perceptions and Reality About the ‘CSI Effect’ Myth Thomas M. Cooley Law Review, 27 (1)
Photo Credit: Flavio@Flickr, Flickr Creative Commons