Stress can thwart our ability to plan ahead by preventing us from making decisions based on memory, according to a new study at Stanford University.

“We draw on memory not just to project ourselves backward into the past but to project ourselves forward, to plan,” said Stanford psychologist Dr. Anthony Wagner, who is the senior author of the paper. “Stress can rob you of the ability to draw on cognitive systems underlying memory and goal-directed behavior that enable you to solve problems more quickly, more efficiently and more effectively.”

The findings are published in the journal Current Biology.

Combined with previous work from Wagner’s Memory Lab and others, the research could have broad implications for understanding how individuals plan for the future — and how a lack of stress may give some people a greater neurologically-based opportunity to think ahead.

“It’s a form of neurocognitive privilege that people who are not stressed can draw on their memory systems to behave more optimally,” said Wagner, the Lucie Stern Professor in the Social Sciences at Stanford’s School of Humanities and Sciences.

“And we may fail to actually appreciate that some individuals might not be behaving as effectively or efficiently because they are dealing with something, like a health or economic stressor, that reduces that privilege.”

For the study, the research team monitored participants’ behavior and brain activity, via functional magnetic resonance imaging (fMRI), as they navigated through virtual towns. After participants became very familiar with the winding routes in a dozen towns, they were dropped onto one of the memorized paths and told to navigate to a goal location.

To test the effects of stress, the researchers warned some participants that they could receive a mild electric shock, unrelated to their performance, during their virtual walks.

The results show that participants who didn’t have to worry about being randomly shocked tended to envision and take novel shortcuts based on memories acquired from previous journeys. Meanwhile, the stressed participants tended to fall back on the meandering, habitual routes.

Before beginning their journey, the participants were virtually held in place at their starting position. Brain scans during this time showed that the stressed subjects were less likely than their counterparts to activate the hippocampus, a brain structure that would have been active if they were mentally reviewing previous journeys.

The stressed individuals also had less activity in their frontal-parietal lobe networks, a part of the brain which allows us to bring neural processes in line with our current goals. Previous research by the team had shown that stress hinders this neural machinery, making it harder for us to retrieve and use memories.

The researchers believe their new study is the first to show how hippocampal-frontal lobe network disruption can thwart a planning session.

“Its kind of like our brain is pushed into a more low-level thought-process state, and that corresponds with this reduced planning behavior,” said Dr. Thackery Brown, who was a postdoctoral scholar in the Memory Lab during this research and is lead author of the paper.

Looking forward, the team is particularly interested in how the link between stress and memory affects older populations, who often experience both health and economic issues. Older adults are also more likely to be concerned about memory loss. Together, these combined stressors could contribute to a declining memory, which could worsen their stress and also impair their ability to deal with it.

Brown has begun conducting research similar to the virtual navigation experiments with participants, ages 65 to 80, to investigate how the links between stress, memory and planning play out in older populations.

“It’s a powerful thing to think about how stressful events might affect planning in your grandparents,” said Brown, now an assistant professor at Georgia Institute of Technology.

“It affects us in our youth and as we interact with and care for older members of our family, and then it becomes relevant to us in a different way when we are, ourselves, older adults.”

Source: Stanford University

Stress Hinders Ability to Plan Ahead By Disrupting Memory