Researchers were able to train unknowing volunteers to develop either positive or negative feelings toward faces where they previously felt neutral. When the study began, the participants were indifferently toward certain facial images, but researchers turned these preferences around without the participants being aware using MRI feedback.
The study suggests that there is a region in the brain that is responsible for judging faces, and also suggests that the MRI technique can be used to train mental processes.
The purpose of the study was to determine if the MRI technique could direct feelings about faces—which is a sophisticated brain function—with the ultimate goal of using the technique for the treatment of mental illness.
Co-author Takeo Watanabe said, “Face recognition is a very important social function for people. Facial recognition is associated with people’s emotions.”
The technique, known as “DecNef,” begins with detecting and analyzing specific patterns in the brain region which is associated with mental state. The decoder was able to successfully analyze the recordings in order to detect distinct patterns in each volunteer’s cingulated cortex, which is associated with positive and negative feelings.
When the patterns were identified, the volunteers were divided into two groups and underwent additional testing in a MRI machine. The volunteers were shown faces, which they previously rated as neutral, while performing an unrelated task. The task was to look at a disk and use their minds to make the disk as big as possible. The larger the volunteers could make the disk, the more money the volunteers were given.
Although the task and the images of the faces may have seemed unrelated, they actually were very much related. The volunteers were unaware of the fact that the disk would only get larger if the MRI reading showed that the volunteer produced the same pattern that was previously captured.
When the testing was done, the volunteers were again asked about their feelings towards previous neutral faces.
The researchers found that those in the positive group increased their rankings of neutral faces and those in the negative group lowered their rankings of the neutral faces. The control group did not change in rankings.
The authors wrote in conclusion, “From all these results we conclude that association of originally neutrally rated faces with covert induction of activity patterns in the single brain region, the cingulate cortex, led to changes in facial preference specifically for those faces, and in a specific preference — positive or negative — direction.”
Orenstein, D., “With MRI technique, brain scientists induce feelings about faces,” Brown University web site, http://news.brown.edu/articles/2016/09/faces, last accessed September 9, 2016.
Shibata, K., et. al., “Differential activation patterns in the same brain region led to opposite emotional states,” Plos Biology, http://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.1002546, last accessed September 9, 2016.