Neuroscience and Society

To Forget or Not Forget? Why and How Memories are Lost

Sharon Samuel


Abstract

    Forgetting a piece of information now and then is a very ordinary part of life; in fact, it is part of what makes us human. But why do we forget some things and remember others? Information is forgotten when our brain fails to retrieve a memory or an interference occurs. Failure to retrieve a memory is usually caused by the absence of stimuli or cues that were formed when the memory was encoded. An interference can occur when  information gets confused with other information. Our memory can be interfered either proactively or retroactively. When a memory has been interfered proactively, an old memory makes it more difficult to remember new information. On the other hand, a retroactive interference makes it harder to remember previously learned information. There is an advantage to losing memories: it makes room for the incorporation of new memories. Our brain gets rid of information by first sorting it out into two categories: information that is impactful and important and information that is not. Pieces of information that fall into the former category become long- term memories, and the rest become short-term memories.

 

How Memories are Formed

    Every day, our brains receive information from our environment. From perceiving the color of someone's socks to knowing how to solve a math equation to even learning about cellular respiration in Biology, any and every small bit of information perceived is processed in the brain, or the limbic system to be exact [1].

    Before discussing why and how we lose memories, we must first review how they are formed in the first place. Memory is not an entity; it is a concept that refers to the process of remembering [3]. Most people talk about their memory as if it were something like bad eyesight, when really, it does not exist in a physical sense like a body part [3].

    Nonetheless, memories do have a physical origin. Memories are formed when neurons communicate with each other through synaptic connections when certain neurotransmitters are present [4]. A neurotransmitter can be thought of as a text message on a phone. A person may not notice one or two messages, but once hundreds of messages are received, one is more likely to notice and respond. This can be related to the idea that the strength of the connections between neurons is what determines how a memory is formed [4].

    “The persistent strengthening of these activated synapses (connections) between neurons is called long-term potentiation," states William Griffith, Ph.D., a cellular neuroscientist and chair of the Department of Neuroscience and Experimental Therapeutics at the Texas A&M Health Science Center College of Medicine [4]. “Long-term potentiation (LTP), is the most recognized cellular mechanism to explain memory because it can alter the strength between brain cell connections. If this strength is maintained, a memory can be formed." LTP acts as an Ethernet cable,  allowing one’s brain to “upload or download” and process information at a higher rate, which may explain why some memories are more vivid than others. The pathway on which the brain connects them performs at a faster pace [4].

 

Failure to Retrieve Memory

    Not being able to retrieve a stored memory is one of the most common causes of forgetfulness.  Retrieval failure is the inability to recall a memory due to missing stimuli or cues that were present at the time the memory was encoded [6].  This theory claims that a memory is temporarily forgotten simply because it cannot be retrieved, but with the proper cue, that information can again be brought to mind [6]. This is also a strategy that is widely used in memorization competitions.

 

Interference with Retrieval

    Interference occurs when information gets confused with other information in our long-term memory [6]. Basically, if cues are too similar, they are more likely to get confused with each other, causing an interference and the wrong memory to be retrieved. There are two of types of interferences that can happen when trying to retrieve a memory: proactive and retroactive.

    Proactive interference is when an old memory makes it more difficult to remember new information [6]. Current information is lost because it is mixed up with previously learned information that may be similar [6].

    Retroactive interference occurs when new information interferes with the brain’s ability to remember previously learned information [6]. It works backward in the sense that it is interfering with previously gained information. The old information is lost due to it being mixed up with new or similar information.

 

The Purpose of Forgetting Information

    Forgetting actually has its fair share of advantages. For example, learning a new locker combination would be accomplished by gradually forgetting the old locker combination. This step is necessary in order to enable space to be made for the new memory. When we acquire new information, like a new locker combination, the brain automatically tries to incorporate it within existing information. This is done by forming associations, and, when we retrieve information, both the desired and associated information are recalled [7].

 

Key Terms (in order in which they appear)

Limbic System- the portion of the brain that deals with emotions, arousal, and memories

Long-term potentiation- the most recognized cellular mechanism to explain memory because it can alter the strength between brain cell connections.

Retrieval failure - the failure to recall a memory due to missing stimuli or cues that were present at the time the memory was encoded.

Interference- occurs when information gets confused with other information in our long-term memory.

Proactive Interference - occurs when an old memory makes it more difficult to remember new information.

Retroactive Interference- occurs when new information interferes with the brain’s ability to remember previously learned information

Long Term Memory - the type of memory stored for an extended period of time

Short Term Memory- the type of memory stored for a short period of time


References


  1. Kumfor, Fiona. (07/06/2015). How Our Brains Forget Information To Make Room For New Memories. Independent. http://www.independent.co.uk/life-style/health-and-families/features/how-our-brains-forget-information-to-make-room-for-new-memories-10303164.html. Retrieved; 14/11/2017.

  2. Jim. (30/11/2011). Forgetting. The Peak Performance Center. http://thepeakperformancecenter.com/educational-learning/learning/memory/forgetting/. Retrieved; 14/11/2017.

  3. Belvoir Media Group. (08/01/2007). Want to Improve Memory? Strengthen Your Synapses. Here's How. NewsWise. https://newswise.com/articles/want-to-improve-memory-strengthen-your-synapses-heres-how. Retrieved; 14/11/2017.

  4. Texas A&M University. (17/05/2016) How does memory work?. ScienceDaily. https://www.sciencedaily.com/releases/2016/05/160517131928.htm. Retrieved; 13/11/2017.

  5. Mohs, Richard. (08/05/2006). How Human Memory Works. How Stuff Works. https://science.howstuffworks.com/life/inside-the-mind/human-brain/human-memory.htm. Retrieved; 13/11/2017.

  6. Dahlitz, Matthew. (27/11/2016). The Limbic System. The Neuropsychotherapist. http://www.neuropsychotherapist.com/the-limbic-system/. Retrieved; 14/11/2017.

  7. Mastin, Luke. (2010). Parts of the Brain. The Human Memory. http://www.human-memory.net/brain_parts.html. Retrieved; 13/11/2017.

Sharon Samuel

Sharon Samuel


My favorite quotes: “Even the darkest night will end and the sun will rise.” “Hoping for the best, prepared for the worst, and unsurprised by anything in between.” “Happiness can be found in the darkest of times, if one only remembers to turn on the light.” “The worst enemy to creativity is self-doubt.” “Life is to be lived, not controlled; and humanity is won by continuing to play in face of certain defeat.”