We might not ever really get brain scans of our actual jurors, but we can learn plenty from brain scans of other people. For one thing, neuroimaging tells us that jurors sort information into narrative segments. We'd be smart to make that job easier for them.
Existing studies show that the brain breaks information in manageable segments the researchers call "narrative events." When something changes in the narrative, the brain works to "close" the segment it was working on and start reorganizing the next information into a new segment.
In a study about to be published in the May issue of Psychological Science, Washington University researchers Nicole Speer, Jeffrey Zacks, and Jeremy Reynolds are adding to the evidence on this topic. The paper is "Human Brain Activity Time-Locked to Narrative Event Boundaries," summarized in Science Daily yesterday and available in full text here.
Be glad you didn't volunteer for this one
You have to feel for the 28 research subjects hooked up to MRI scanners in this experiment. "A pillow, washcloths, and tape" -- tape! -- "were used to minimize head movement, and headphones and earplugs were used to minimize noise from the scanner." They watched a screen where the words of a story, describing a young boy's activities in a typical day in the 1940s, were projected -- "in 52-point, white font on a black background," one word at a time.
The subjects weren't asked to do anything with the story, just watch it, and the scanners recorded their brain activity while they watched. Then the researchers asked the subjects to go back and divide the story into "events."
We create "narrative events" without trying
The MRI results showed that when the subjects were watching the text without trying to look for events, their brains were active at the precise points where they later, consciously, drew the dividing lines between events. That is, their brains were working to divide the story into "event" segments, even when they weren't asked to do that.
What's an event? A new one starts when the characters, place, or time change, but also when the characters' goals change, they start working with different objects (perhaps playing with a ball or reading a book, in the case of the boy in the story), or new causal relationships are revealed. When we hit an event "boundary," our brains go to work:
As incoming information about the current event becomes less consistent with the current mental model, readers are more likely to update the current model to more accurately represent the state of the world.
What does it mean?
Trial lawyers already know it's best to present information as a narrative, so what does this research add? Two things, it seems to me. First, when you are presenting narrative, you can go with jurors' flow, using clear transitions to break the information into the same kind of segments they will. If you break where they don't, and don't where they do, they'll be working behind the scenes to reorganize. The study doesn't say so, but it seems logical and familiar to conclude that if you save them that work, they'll hear more of what you say.
Second, you can't always present in narrative form. For one thing, a single story usually needs to come out through several witnesses. For another, some information needs to come out in categories -- lists, charts, whatever. A profit-and-loss statement, for example, contains little mini-stories (how come Hollinger sent Conrad Black to Bora Bora?), but in the end it's organized by accounting lines. When you can't tell a story, this research suggests you'd be wise to communicate with extra clarity the organizational structure that best works for your information, since the listeners' brains won't be providing it naturally.
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Language note: if you're into neuroimaging, you'll especially love this paper. It has sentences like "An additional T2-weighted fast turbo spin-echo scan acquired structural data in the same planes as the functional scans, in order to facilitate the mapping between the functional and structural data." Great stuff.
(Photo by Andrew at http://www.flickr.com/photos/polandeze/423230640/; license details there.)
