Persuading the Cro-Magnon Mind – Juror “Information Overload”

By Dave Nugent

Why is it important that a trial attorney understand the retention capabilities of his jurors’ minds? Consider all the information a juror is confronted with over the course of a trial: jury instruction; defense and plaintiff argument; expert & witness testimony; cross; demonstrative content; exhibits; etc. In complex matters, it is vital to know how much the juror can absorb, how much (s)he can accurately retain to memory and how to hone, exemplify and filter your argument accordingly … to assure survival of key information to deliberation.

cro-magnonartclassThe brain that we are born with today is almost identical to the Cro-Magnon brain of forty thousand years ago. This same brain that once could focus, without distraction, on painting beautiful animal figures in Lascaux Cave is today regularly tasked and multi-tasked with taking in greater volumes of complex information.

As a direct neurological descendent of the Cro-Magnon, how much information can a juror take in, retain and make sense of in deliberation? Not all that much, argued Psychologist George Miller in his paper “The Magical Number Seven, Plus or Minus Two”. In preparing your case argument and visual presentation, Miller’s conclusion is one key bit of information to retain.


Working memory temporarily stores and makes sense of information to solve complex problems, including language and – most importantly for our purposes here – oral & visual instructions. We possess inherited, built-in limitations to our working memory – a “mental bandwidth”. Miller posited the number 7, plus or minus 2, as the average number of pieces of information that our working memory can retain and work with simultaneously.

Brain-Open_IdeasResearch at Temple University – utilizing MRI technology – showed that as the brain processed information, the pre-frontal lobe (your “make sense” center) lit up, as it should. But when presented with increased amounts of information, it “went dark” – activity stopped. In short: too much information caused brain freeze. If our “Post-Magnon” juror is presented with argument points in excess of Miller’s seven pieces of information at any given time, his ability to retain information and make decisions breaks down – he suffers “information overload.”

“A good story cannot be devised; it has to be distilled.”   Raymond Chandler

Less is better. When strategizing your argument, try to break any theme or subject point, or an overview of your argument, down to 3 or 5 key points to compose your story. All other facts and events need be sub-theme and foundation. Make it easier for your decision-makers with a conclusive statement like, “If you remember just one thing, let it be…

“Simplicity is the ultimate form of sophistication.”   Leonardo da Vinci

Successful design of your supporting trial graphics requires the same respect for your juror’s cognitive capacity. For example …

For timelines, events need be limited to the theme or argument made by that timeline. Normally, 3-6 key events are the maximum focus for any timeline to take on (unless the point of your timeline is volume or repetition), and those should “pop out” visually from the other plotted events. Additional events need be necessary contextual support or help show causal relationships, motivation, etc. Resist the impulse to qualify and embellish – that, the presenter should do orally.

Master Timelines often end up using the “kitchen sink” content inclusion criteria. Display only the key story-argument points and events … leave the drill-down themed detail events to separate sub timelines.

“Take your audience out of the puzzle-solving business.”   Edward Tufte

Graphs, charts, tables and illustrative slides need to be designed for juror comprehension within 3-6 seconds. Multi-tasking slides require jurors to sort and multitask … and studies show this is not a skill of modern man, contrary to popular myth. If you need to explain your demonstrative – it’s not working.

Clearly, avoiding information overload to keep your juror’s pre-frontal lobe a smooth-running, but unburdened, data-processing machine will greatly increase your chances of imprinting that juror’s memory with key favorable impressions. That in turn leads to sound jury decision-making and obtaining the results you desire.


Reference: George Miller, The Magical Number Seven, Plus or Minus two, 1956. Torkel Klingberg, The Overflowing Brain, 2009.