Could Surprise Enhance Memory?

By: Inas Essa

There was an old, widely-spread trick about a better way to retrieve important, yet hard-to-stick information in exams: switch a ring you usually wear to another finger; during the exam, when you find its place changed, you would recall the piece of information you encoded. Another way we can trick our minds and do better in exams is by implementing surprise while encoding the piece of information, as a new study by University of Manchester neuroscientists has shown. So, how could surprise facilitate learning or memory retrieval?

Expectation Violation Enhances Memory

Encoding and retrieval are the two ways our brains process information. First, we encode the information in different ways: reading, watching, listening, etc. Then comes the retrieving of the information we already acquired and encoded in our brains. This means that the brain processes information by shifting between encoding and retrieval.

Previous research has indicated that surprise turns on the brain’s learning mode by triggering an adaptive encoding mechanism that would result in better memory for unexpected events. The current study investigated how the brain uses the mechanism when we are trying to retrieve information.

In the recent study, participants were shown pictures of objects that were either natural—such as fruit, trees, and flowers—or manmade—such as a computer mouse and telephone. Then, they were trained to expect manmade or natural objects using cues, such as a triangle or a square, while researchers used a functional MRI scan to reveal which regions of the brain were used to learn and retrieve the information.

Surprise Boosts Memory

Results have shown that when an unexpected event—such as a triangle preceding a natural object—the participants’ memory was boosted. The fMRI scan showed activation in the brain’s hippocampus—the memory center, midbrain regions that releases dopamine, and occipital cortex—the vision center. On the other hand, when a sequence of two unexpected events happened, no enhancement in memory performance happened.

“We already know that if the expectation is violated before or during learning, it triggers an adaptive mechanism, resulting in better memory for unexpected events. This experiment shows how the mechanism is also affected when we are trying to retrieve information,” says Lead author Dr. Darya Frank, a cognitive neuroscientist from the University of Manchester.

These results could be explained as: the hippocampus encodes and retrieves memories, and the two mechanisms stay in conflict with a finite amount of resources to allocate to either. The element of surprise boosts our memory because when something unexpected happens, our brain focuses on the outside environment so it can learn something new, something it did not initially expect.

Dr. Frank added: “Though our study did not assess the impact of these findings on exam revision and performance, it is logical to see its implications  So, when the goal is to retrieve information—encountering surprising events like revising in café or other unfamiliar surroundings would engage an encoding mechanism that may enhance memory for a future exam. But the reverse is also true: when trying to remember something already learned during the exam itself, a familiar and expected environment could be helpful, and support retrieving information from memory”.