Biologically speaking, the mechanism of stress does not really differ across circumstances, environments or situations. This means that “good” stress (mechanistically speaking) is inseparable from “bad” stress. So, what’s this mechanism?

For the purposes of this column, we can boil stress down to one brain structure and two neurochemicals.

The brain structure of importance is the hippocampus. In order to form new memories for facts or events, information must pass through the hippocampus, making it our gateway to memory.

The neurochemicals of importance are cortisol and ARC proteins . Within the brain, cortisol is largely neurotoxic and damages neurons, while ARC proteins serve to mould and reshape the structure of neurons.

Whenever a stress response is triggered, cortisol floods into the hippocampus and begins damaging neurons. This damage, in turn, triggers the release of ARC proteins, which flood into the hippocampus and “battle” cortisol: essentially, keeping it occupied to avoid further neuron damage.

If this is the basic mechanism, why is stress sometimes beneficial and sometimes detrimental? It turns out, there are three primary reasons.

The first concerns stress duration. During short-duration stress, the stress response abates after a few seconds, minutes or hours. Once this happens, cortisol leaves the hippocampus, but ARC proteins stick around and begin repairing any damaged neurons, making them stronger than they were before.

By first damaging then bolstering the memory gateway, the stress mechanism ensures that we form deep, durable memories for short-term stressors.

Conversely, during long-term stress (days, weeks, months), cortisol remains in the hippocampus and stores of ARC proteins eventually run dry. Once this occurs, cortisol has free rein and begins killing cells within the memory gateway. By first damaging then killing the memory gateway, the mechanism ensures that we do not form deep, durable memories for long-term stressors.

To help make sense of this process, imagine you stepped in a bear trap. If you were able to quickly remove the trap, then this would be an event worth learning from. The short-term stress response would ensure that a deep memory is formed, helping you to avoid making this same mistake in the future.

However, imagine if you were stuck in the trap for 72 hours before help arrived. In this instance, there is little learning to be done and no reason to create a deep memory for prolonged suffering. As such, the long-term stress response deactivates memory formation until the helpless situation is resolved.

With regards to education, this all means that short-term stressors might be worthwhile. So long as students feel supported and recognised, then embracing high expectations, relevant challenge and academic repercussions may actually boost learning and memory. However, when students undergo long-term stressors (whether personal or academic), we can expect memory to suffer significantly.

This is why much trauma-informed education focuses heavily on relationships and stress reduction. Until school is understood as a safe place and teachers are recognised as reliable influences, very little (if any) classroom learning will occur.

Beyond duration, the other two reasons why the same stress mechanism can sometimes be beneficial or detrimental concern intensity and interpretation. We will explore these two aspects in part two of this column.

Jared Cooney Horvath is a neuroscientist, educator and author. To ask our resident learning scientist a question, please email AskALearningScientist@gmail.com

This article originally appeared in the 1 May 2020 issue under the headline “Good stress vs bad stress: what’s the difference?”