To make a memory

Dr. Patrick Davidson discusses the science behind how a memory is made, stored and processed in relation to emotion.

Graduating from university. Your wedding day. The death of a parent. These are moments that create memories. The connection between a person’s memory and the emotions he or she happens to be feeling at the time the memory is created is not fully understood, still it is accepted that emotions contribute to making and storing vivid memories. Memories that contain emotionally charged moments tend to provide the most vivid and detailed memories.

Emotionally-charged memories can be divided into two categories; personal, or autobiographical, and public. The vivid long-lasting recollection of an emotionally-charged public event is called a flashbulb memory. A flashbulb memory differs from a typical autobiographical memory in that it is more involved with the contextual elements surrounding the memory, as opposed to the actual content of the memory.

“The quintessential example we use is a bank robbery. If you’re involved in a bank robbery, everybody focuses on the gun held by the bank robber and less on the face of the bank robber.”

According to Dr. Patrick Davidson, a professor of neuropsychology at the University of Ottawa, “flashbulb memories occur when we tend to hear shocking, surprising news, like of a terrorist attack or a natural disaster, and we feel this visceral emotional charge within us that creates this memory of where, how and when we learned the news, and what emotions we were feeling at that particular time.”

Davidson says, studies of flashbulb memories tend to focus on shocking and typically negative public events, as opposed to personal events, because they are less specific to each individual and therefore the responses are easier to verify and study. Negative events tend to be surprising and defining at a societal level.

“The quintessential example we use is a bank robbery. If you’re involved in a bank robbery, everybody focuses on the gun held by the bank robber and less on the face of the bank robber. The way your brain works when your emotions are running high, you may be paying attention to things or processing information differently than in an everyday situation and that will affect the memory you have of that event,” says Davidson.

Reaction vs. Intensity

There are two aspects of emotion involved when creating a memory. The first is the emotional reaction you may be feeling at the time the memory is created, such as happy, sad, jealous or scared. The second is the intensity of that particular emotion.

Though it is perceived that emotional memories are stronger or more vivid, “it’s not always the case that emotion makes events easier to remember,” says Davidson.

Davidson uses the Yerkes-Dodson curve to illustrate how high emotional arousal can influence the processes your brain goes through when creating a memory. This graph demonstrates how a memory can be stronger or more significant as emotional arousal increases, but only until your brain reaches a certain emotional peak. The descent after this emotional peak, when emotions continue to become more and more intense, influences the encoding process involved in making and storing a memory.

Yerkes-Dodson Curve representing the relationship between Arousal and Performance

Errors of Omission and Commission

“You may end up missing certain details or forgetting a piece of information from an event where emotions are running high. You don’t remember things the same way you would if you were operating at a less intense level of emotional arousal,” says Davidson.

Davidson says not only do we leave pieces of information out, but we add things and we are not necessarily aware that this has happened. It is also common to have two pieces of information, from two different experiences and get those mixed up, or think they belong to the same memory.

“You’re definitely going through these same processes when you’re making a flashbulb memory and the more we understand about normal brain processes, the more we realize that it’s just a slight modification or boost of what’s taking place when your brain is creating everyday memories,” says Davidson.

The Brain

“The whole brain is needed to make, store and retrieve a memory. The temporal lobe, the occipital lobe, the parietal lobe feed into the hippocampus and provide it with the information you are seeing and experiencing,” says Davidson.

The hippocampus is the area of the brain most-involved with memory storage and retrieval, but it doesn’t work alone when creating emotional memories. There is a small, almond-sized area of the brain next to hippocampus called the amygdala that is involved in creating explicit memories.

Right Hemisphere of brain

“One way in which memories are represented at the neuron level is the interconnectivity between neurons. When a memory is being stored or retrieved, one neuron is firing an action potential, eliciting an action potential from the next neuron, and so on. This is when the amygdala becomes important because this is where there seems to be some cross-talk between the amygdala and the hippocampus that helps us encode, store and retrieve emotional memories,” says Davidson.

Though the link between memory and emotion is still being explored, it is clear that when it comes to memory, no one is objective, says Davidson.