Read Part 1 of the Memory series.

Throughout this blog series, we’re attempting to unravel some of the mysteries surrounding human memory. We know a lot about how memories are recorded, as detailed in the previous post, but a great deal of ambiguity surrounds the reasoning behind which memories are stored and which ones are discarded. You might notice this when interviewing subjects for one of your projects. For instance, a company’s CEO may vividly remember receiving an award in 1986 but fumble with the details of an accolade from the previous week. In this post, we’ll examine the role that other factors, such as emotions, play in identifying short- and long-term memories.

There’s a common misconception that our inability to remember events or details is linked solely to brain function.

There’s a common misconception that our inability to remember events or details is linked solely to brain function. If you’re struggling to recall the name of a childhood friend, it’s natural to think your memory has weakened, and that you’ll either need an expert opinion from a medical professional or you’ll need to increase your intake of nutritional supplements to jump-start brain activity. But the factors affecting your memory aren’t always internal. Mild medical conditions, like sleep apnea, can cause memory loss as well as medications (such as antihistamines, sleeping pills, and cholesterol-lowering meds).

Furthermore, your emotional connections to your memories (be it stress, anxiety, happiness, or sadness) play a major role in whether those memories become permanently encoded or dumped from the hippocampus. When we experience something, that information is sent to the hippocampus, where synapses are formed, and decisions are made about what happens to your newly formed memories. The hippocampus’ process of elimination is one of the most mysterious aspects of memory storage, but research shows that it favors the enriching and novel experiences over the mundane.

Emotional Memory Enhancement

The dull, routine things are harder for us to remember because we don’t have any significant attachment to them. You may not recall locking the front door but there’s (usually) no question that it’s actually locked. You go through this repetitive motion every day. It’s quick, simple, and something you could do in your sleep. Relatively speaking, it’s not important enough to have a permanent home in your brain. It seems these types of actions would free up the brain to form more impactful memories. But everyday habits, while necessary, can negatively impact memory. Though these memories are short-term, they still require effort from your hippocampus. And if routines make up the bulk of your day, your brain could spend a majority of its time dumping unimportant memories instead of encoding more important long-term ones.

“Only unsettling inner events can help to awaken us and sharpen our memory,” writes Psychology Today’s Mark E. Williams, MD. Williams reasons that habits prevent us from getting to know ourselves on a deeper level because we’re too busy going through the motions and leading predictable lives to experience new things. The novelty of those new experiences is what drives the creation of long-term memories.

Emotional memory enhancement is the cognitive process in which memories attached to arousal become the frontrunners for long-term encoding.

The concept of emotional memory enhancement best describes why. A 2009 study by Elizabeth A. Kensinger examined the phenomenon of emotional memory enhancement, and how this enhancement affected the encoding and accurate retrieval of those memories. Emotional memory enhancement is the cognitive process in which memories attached to arousal become the frontrunners for long-term encoding. This arousal is basically any event that stimulates the release of stress hormones. The hormone release encourages collaborations between the hippocampus and various other parts of the brain including the amygdala and brain regions responsible for processing sensory and mnemonic information. There are more brain functions and regions working during this release. Thus, there’s a much higher chance of these memories being saved.

The emotional connection to this memory doesn’t just happen when the memory is encoded. It continues as the memory is consolidated and stored in its permanent location. And those emotions are referenced again when the memory is retrieved. The emotion, which Kensinger refers to as arousing information, is more likely to be encoded along with the memory, as opposed to non-arousing information.

The Emotional Hangover Study

Several other studies have led to similar findings. Take for instance a study published in Nature Neuroscience in 2016. This study explored “emotional hangover”, a concept in which a person’s emotional state affected the quality of their memory. In the study, participants were shown two sets of images, one meant to elicit emotional responses and one neutral. Participants who viewed the emotional images first could recall the second set of images more accurately. Those who viewed the neutral images first struggled to recall the more emotional set of photos. The “emotional hangover” study showed that increased brain activity from arousal not only improved the encoding of one memory but those which followed immediately after.

Prior to the study, it was believed that emotionality would only affect memories we’d already stored or were in the process of storing. But now, it appears that emotions could also affect future encoding.

The intensity of the emotions encoded with these memories is something we feel later during retrieval. Writer and psychologist Mary C. Lamia Ph.D. believes in the strength and purpose of these memories — that they’re meant to guide us toward better decisions and continually remind us of important life lessons. But our emotional memories can also disrupt our present because of their vividness. “If everything seems to trigger a memory for you,” she writes, “especially ones that activate emotional responses, you can become derailed from the path you are taking and instead focus on the memories.” There are times when emotions can also distort, rather than enhance, our greatest, or worst, memories.

Emotions and memories are more intertwined than scientists and researchers initially speculated. While their relationship is still not perfectly defined, it’s becoming clearer with each additional study: our feelings and connections to our memories may hold the ultimate key to understanding how memory functions.

When you examine your life, think about how the memory-emotion connection impacts you daily. Have you found yourself struggling to remember things? Is your day full of routines and habits but few novel experiences? What’s your emotional connection to your memories? Understanding these aspects about yourself could also lead to insights that make you a better interviewer and better able to draw out memories from your subjects.

Next up, we’ll dissect memory retrieval, the least defined part of the memory storage process, and how it affects our memory’s accuracy.

Read Part 3.