September 19, 2012
Brain Activity Helps Predict Individual’s Test Performance
Lee Rannals for redOrbit.com — Your Universe Online
Scientists are monitoring brain activity to help try and predict how well someone will perform on a test they have been studying for, and how to better improve study habits.Researchers at Sandia National Laboratories have shown it is possible to predict how well people will remember information. The team demonstrated predictions based on the results of monitoring test volunteers with electroencephalography (EEG) sensors.
Laura Matzen of Sandia´s cognitive systems group said: “If you had someone learning new material and you were recording the EEG, you might be able to tell them, ℠You´re going to forget this, you should study this again,´ or tell them, ℠OK, you got it and go on to the next thing."
Matzen and her team monitored test subjects' brain activity while they studied word lists, and they used the EEG to predict who would remember the most information.
The team had a baseline of what brain activity looked like for good and poor memory performance, because they already knew average percentage of correct answers under various conditions.
The computer model predicted five of 23 people tested would perform best, and the team said the model was correct. Those people remembered 72 percent of the words on average, compared to 45 percent for everyone else.
Ultimately, the study is part of Matzen's long-term goal to understand the Difference Related to Subsequent Memory, or Dem Effect, which is an index of brain activity encoding that distinguishes subsequently remembered from subsequently forgotten items.
Matzen is interested in what causes the effect, and what can change it, with hopes that her research will eventually lead to improvements in how students learn. She said she hopes to discover how training helps people performing at different levels and whether particular training works better for certain types of people.
One of Matzen's goals is to find out whether recording a person's brain activity while they use their natural approach to studying can predict what kind of training would work best for that person.
A next step would be to use real-world memory working tasks, like what military personnel would have to learn as new recruits.
The researchers used about 90 volunteers in a second part of the study, who spent nine to 16 hours over five weeks in testing for the memory training techniques study. Their first session developed a baseline for how well they remembered words or images.
The team used a control group with no training for the study, and a second group who practiced mental imagery strategy. A final group went through "working memory" training to increase how much information they could handle at a time.
Each volunteer in the study watched a screen that flashed words or images for one-second, and then were given periodic quizzes on how well the person remembered what was shown.
“It´s designed to be really difficult because we want lots of room to improve after memory training,” Matzen said in a press release.
The team divided the test into five sections, each about 20 minutes long followed by a break to keep volunteers alert.
When performance was compared before and after training, the control group did not change, but the mental imagery group's performance improved on three of the five tasks.
“Imagery is a really powerful strategy for grouping things and making them more memorable,” Matzen said in the release.
The working memory group did worse on four of the five tasks after training.
Matzen said the imagery training group learned a strategy, while working memory training simply tried to push the limits of memory capacity.
Although the imagery group performed better, they made more mistakes than the other groups when tested on "lures" that were similar as the items they had memorized.
“They study things like ℠strong adhesive´ and ℠secret password,´ and then I might test them on ℠strong password,´ which they didn´t see, but they saw both parts of it,” Matzen said in the release. “The people who have done the imagery training make many more mistakes on the recombinations that keep the same concept. If something kind of fits with their mental image they´ll say yes to it even if it´s not quite what they saw before.”
She presented the results of the first part of the study in April at the Cognitive Neuroscience Society conference in Chicago. She presented the preliminary findings on the second part of the study this summer to the Cognitive Science and Technology External Advisory Board.