A new experiment from German scientists suggests stress invokes our brain to use different and more complex processes during learning.
In the study, cognitive psychologists Drs. Lars Schwabe and Oliver Wolf discovered that the presence or absence of stress is associated with use of different brain regions and different strategies in the learning process.
Stress appears to make the brain work harder and use a more complex approach when learning. Study findings are reported in the Journal of Neuroscience.
Researchers discovered that non-stressed individuals applied a deliberate learning strategy, while stressed subjects relied more on their gut feeling.
“These results demonstrate for the first time that stress has an influence on which of the different memory systems the brain turns on,” said Schwabe.
In the study researchers analyzed the data from 59 subjects. Two groups were assigned with one group asked to immerse one hand into ice-cold water for three minutes (while being observed by video surveillance).
As expected, this activity stressed the subjects with data collected and confirmed by hormone assays.
The other group was asked to immerse one of their hands in warm water. Then both the stressed and non-stressed individuals completed a task called weather prediction. The task involved having subjects look at playing cards with different symbols and then using the cards to predict which combinations of cards forecast rain and which sunshine.
Each combination of cards was associated with a certain probability of good or bad weather. People apply differently complex strategies in order to master the task.
During the weather prediction task, the researchers recorded the brain activity with MRI.
Researchers found that both stressed and non-stressed subjects learned to predict the weather according to the symbols. However, the way in which they learned the task varied.
Non-stressed participants focused on individual symbols and not on combinations of symbols. They consciously pursued a simple strategy.
The MRI data showed that they activated a brain region in the medial temporal lobe – the hippocampus, which is important for long-term memory.
Stressed subjects, on the other hand, applied a more complex strategy.
They made their decisions based on the combination of symbols. They did this, however, subconsciously, i.e. they were not able to formulate their strategy in words.
In this group of stress participants, brain scans showed that the so-called striatum in the mid-brain was activated — a brain region that is responsible for more unconscious learning.
“Stress interferes with conscious, purposeful learning, which is dependent upon the hippocampus,” concluded Schwabe. “So that makes the brain use other resources. In the case of stress, the striatum controls behavior — which saves the learning achievement.”
Source: Ruhr-University Bochum