Why do we forget certain things but remember others

Q: Why do we forget certain things but remember others, even though our brain is known for its memory storage capabilities? Is there a scientific explanation for this phenomenon?

Krishna: Selective memory (also sometimes referred to as selective amnesia) can be clinically defined as “the ability to retrieve certain facts and events but not others.

Memory is a complicated process

Why do we remember some events, places and things, but not others? Our brains prioritize rewarding memories over others, and reinforce them by replaying them when we are at rest, according to research published in the journal Neuron (1).

Rewards help you remember things, because you want future rewards. The brain prioritizes memories that are going to be useful for future decisions. It’s estimated that we only retain detailed memories for a small proportion of the events of each day, the research paper says. People with very detailed memories become overwhelmed with information. So if the brain is going to filter information and decide what to remember, it makes sense to save those memories that might be most important for obtaining rewards in the future.

Although this study did not measure it directly, these interactions were likely related to release of dopamine, a neurotransmitter that is released in the brain when we expect rewards. Conditions such as Parkinson’s disease or aging are linked to reduced dopamine and often involve memory defects.

The results show how memory could be biased toward the high points of experience. It speaks to a memory process that is normally hidden from us. Are you remembering what you really need to know? It could depend on what your brain does while you are at rest (2).

Forgetfulness can arise from stress, depression, lack of sleep or thyroid problems. Other causes include side effects from certain medicines, an unhealthy diet or not having enough fluids in your body (dehydration). Taking care of these underlying causes may help resolve your memory problems.

Emotion has a substantial influence on the cognitive processes in humans, including perception, attention, learning, memory, reasoning, and problem solving. Emotion has a particularly strong influence on attention, especially modulating the selectivity of attention as well as motivating action and behavior. This attentional and executive control is intimately linked to learning processes, as intrinsically limited attentional capacities are better focused on relevant information. Emotion also facilitates encoding and helps retrieval of information efficiently. However, the effects of emotion on learning and memory are not always univalent, as studies have reported that emotion either enhances or impairs learning and long-term memory (LTM) retention, depending on a range of factors (3). Emotional influences can either enhance or impair learning and retention of new information—possibly bringing on selective memory.

Other possible causes can include (4):

Imbalanced Emotions

Individuals who live with personality disorders or other similar ailments may be more susceptible to emotional highs and lows that can precede the formation of selective memory. An example of this can be bipolar disorder, which is generally associated with manic highs and depressive lows. 

Poor Nutrition

Another potential factor that can be involved in selective memory can come in the form of poor diet habits. The food that people consume can impact their lives in many ways. Therefore, it may come as no surprise to many that certain foods can have long-term impacts on an individual’s memory and affect their thinking capabilities.

Preservatives, processed foods and drinks, chemical additives and foods with high amounts of sugar have all been scientifically linked to direct neurological effects. For this reason (and many others), the consumption of healthy foods (fruits, fish, vegetables and poultry) is generally strongly encouraged over other options when possible.

Human Willpower

People are scientifically suggested to have the power to repress and eventually forget certain memories. Intentionally repressing a memory for long enough can cause one to forget it.

While selective memory is generally regarded as a negative occurrence, there are certain instances where it can be helpful to one’s overall quality of life. An example of this can be seen in cases of post-traumatic stress disorder (PTSD) or other instances where painful events may do more harm than good. It is generally inadvisable to repress memories as a manner of dealing with challenges from the past, however. 

Diseases, Disorders And Aging 

The effects of aging can manifest in the form of memory discrepancies and changes. Selective memory in this context can be a common occurrence. Additionally, conditions can lead to selective memory and memory changes. Common memory disorders of this nature include, but are not limited to Alzheimer’s disease, Parkinson’s disease, amnesia, stress and dementia. 

While aging can affect everyone differently, many find that a healthy lifestyle (including exercise, human interactions and a nutritious diet) can serve as a deterrent to the formation of memory ailments—such as those listed above.

Selective memory can be incredibly layered. Many of these variations can come in the form of amnesia or hypermnesia. These conditions can range in severity and manifestation. In its mildest capacity, amnesia can cause someone to have difficulty in remembering certain facts or pieces of information. 

In more severe degrees, an individual who experiences amnesia may lose ownership of virtually all their memories. Extreme amnesia generally surpasses selective memory; while the latter might only pertain to certain memories. The former (at its most severe) can cause the person to lose touch with all their memories.

Another form of amnesia (and selective memory) can manifest in the form of forgetfulness across various time periods. Clinically known as lacunar amnesia, someone who has this ailment may subsequently lose the memory of seconds, hours or even days of a particular event. Sometimes lacunar amnesia can be referred to as a blackout—and it can be engendered by drugs, alcohol, trauma or other relevant stimuli.

Evocation amnesia can show similarities to lacunar amnesia as a condition. Instead of forgetting various periods within an event, this version of selective memory dysfunction can prompt the person living with it to lose recollection of the specific names of individuals or inanimate objects. 

For instance, an evocative amnesiac might meet various people at events, yet subsequently, fail to remember their names. This can occur despite the possibility that the person may remember everything else about the people they encountered— other than their names.

Hypermnesia is the final variation of selective memory that is mentioned here. This variation of selective memory is considered by many to be the inverse of amnesia. Rather than the increasing lack of memory (amnesia), hypermnesia can occur when an individual might seem to remember information encountered all at once.

If you take care of these things, naturally your selective memory problem will disappear.

Footnotes:

1. https://www.cell.com/neuron/fulltext/S0896-6273(16)00018-0

2. https://www.ucdavis.edu/news/memory-replay-prioritizes-high-reward-...

3. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5573739/#:~:text=Emoti....

4. https://www.betterhelp.com/advice/memory/an-overview-of-selective-m...