University study shows effect of positive and negative distractions on working memory
November 17, 2015
By Susan Szuch
Imagine: A hundred thousand years ago, your ancestors are working to gather food, their attention focused on remembering where the ripe fruits they saw earlier were. Suddenly, a predator distracts them, diverting their attention from the task and making them run.
It’s been known that negative distractions, like predators, impact our ability to remain focused on a task, but the influence of positive distractions on the task at hand was not known.
“(Positive and negative emotions) are evolutionarily set to influence us differently,” said Associate Professor of cognitive neuroscience Florin Dolcos. “Instead of having us focus on things to take action if there’s something negative, (positive emotions) actually have a kind of mind-opening effect of the attention, rather than tunneling the attention to a danger you have to be careful of.”
While previous studies indicate that negative distractions impair our ability to recall recent information, the question remains about the effect of positive distractions.
A recent study by Doclos and Alexandru Iordan, graduate student in cognitive neuroscience, has been exploring just that.
The study, “Brain Activity and Network Interactions Linked to Valance-Related Differences in the Impact of Emotional Distraction,” was published in early November in the journal Cerebral CortexRB.
Subjects in the study were given a series of faces to look at and told to keep them in mind during a short delay where they were shown positive, neutral and negative images, then asked if they’d seen specific faces or not.RB
The images they selected were chosen so they could test both the reaction and the intensity of the reaction — in fact, they had to eliminate some of the most intense images.
The study used MRI machines to look at brain activity and see which structures in the brain were working while subjects completed the taskRB.
What they found was that multiple brain regions were involved in processing the information, and that negative distractions can make certain brain regions work together, even if they don’t normally work together.
One of the regions they found that was affected was the lateral parietal cortex, which is involved in working memory processing RB— similar to when you are given a phone number and have to remember it until you can write it down or put it in your phone. It’s also more involved in paying attention and being involved in the outside world.
The other region was the medial prefrontal cortex, which is sensitive to emotions. The MPC is also part of a network called the default mode networkRB, which is active when we’re not paying attention to the outside world and are introspective.
The study found that the MPC communicated more with the LPC under negative distractions than positive ones, and could explain why processing negative information interferes with working memory.
“The medial prefrontal cortex and the lateral parietal cortex are parts of different brain networks, and they do not typically communicate with each other when we are trying to keep information active in our mind,” Iordan said. “Their increased coupling under negative distraction may explain why the negative stimuli were more impairing for cognitive performance.”
Iordan and Dolcos hope that this research can help shed more light on how people with depression or post-traumatic stress disorder process information, and subsequently, what’s happening in their brains.
Iordan noted that while it’s something that needs to be tested, researchers could see how the face recall task works with patients who have depression and suffer from anhedonia, or a lack of sensitivity to positive emotionsRB.
“Certain clinical conditions, such as depression, are also characterized by changes in the way we process positive emotions,” Iordan said. “It is possible that, compared to healthy individuals, patients with depression may find positive stimuli more interfering in this context, because they are discordant with their mood.”
He also looks forward to the research that may potentially stem from this study. Discovering what brain regions are sensitive to different kind of emotions and how that may be linked to depression or PTSD can help develop more targeted treatments for those mental illnesses, as well as preventative measures.
“In the end, it’s not only about finding what is wrong, but also about preventing people from developing emotional disorders,” Iordan said. “It’s also important to know how the healthy brain works so we can foster this healthy state before a clinical condition develops.”