Imagine the usefulness of knowing if someone is drawing on a memory or experiencing something for the first time. "No, officer, I've never seen that person before."
That's possible, using an algorithm that interprets brain scans developed by a team of Stanford researchers led by psychology professor Anthony Wagner, PhD. But according to a Stanford Report article, it's also possible to fool that same program when subjects are coached to hide their memory.
The program, or decoder, capitalizes on the complexity of memory, which taps many different regions of the brain. They use functional magnetic resonance imaging (fMRI) to view which parts of the brain are active.
Hoping to illustrate the limits of their own creation, the researchers asked 24 study participants to study a series of faces. The next day, they exposed them to some of the same faces mixed with entirely new faces:
"We gave them two very specific strategies: If you remember seeing the face before, conceal your memory of that face by specifically focusing on features of the photo that you hadn't noticed before, such as the lighting or the contours of the face, anything that's novel to distract you from attending to the memory," said Melina Uncapher, PhD, a research scientist in Wagner's lab. "Likewise, if you see a brand-new face, think of a memory or a person that this face reminds you of and try to generate as much rich detail about that face as you can, which will make your brain look like it's in a state of remembering."
With just two minutes of coaching and training, the subjects became proficient at fooling the algorithm: The accuracy of the decoder fell to 50 percent, or no better than a coin-flip decision.
The new study shows that imaging technology alone will not be able to "pull about the truth about memory in all contexts," Wagner said. And, as pointed out in the article, he "sees [the results] as potentially troubling for the goals of one day using fMRI to judge 'ground truth' in law cases."
Previously: Memory of everyday events may be compromised by sleep apnea, The rechargeable brain: Blood plasma from young mice improves old mice's memory and learning, Researchers explore the minds of man's best friend using fMRI technology, Using fMRI for lie detection and Brain scan used in court in potential fMRI first
Photo by David Schiersner
