By Dr. Ken Broda-Bahm:
This is one of those times I expect my title to be met with a, "Well, no kidding." Attorneys and expert witnesses know the demands of conveying often complex methods and conclusions and know the drill: simplify, simplify, simplify. So lawyers and witnesses know to keep it basic. But do they? Not as much as we would like. Research (like Greene & Bornstein, 2003) shows that jurors have trouble comprehending evidence, and practical experience continues to remind us that out of all of the descriptions, reasons, methods, and conclusions an expert presents on the stand, jurors in a post-trial interview will understand and remember a handful at best.
So what is going on? Lawyers and experts get the need for simplicity, but are still committed to a set of beliefs and practices that end up maintaining a level of complexity that can put testimony out of reach. For example, one belief that I've seen embraced by experts and lawyers alike is the belief that once an explanation or a definition is provided, the witness can go ahead and use the unfamiliar terms and concepts, trusting in the jury's ability to remember and apply that definition. But new research is pointing to the probability that it isn't simply a lack of comprehension that impedes understanding, it is cognitive load. The idea is that our ability to process, remember, and understand is finite and breaks down quickly once it is overtaxed. This post takes a look at one of the most important implications this has for lawyers and experts: The task isn't just to make it technically understandable, it is to make it easy.