Memories: Why we forget and remember


Memories allow us to remember, by storing data within the brain and retrieving that information when needed. It is essential to our lives, as without it, it would be very hard to know anything at all. There is no doubt that different people have various capabilities of being able to remember things, and this tends to become worse as people age, due to dementia or even stress.

There are different types of memories, with the most basic being the sensory memory. This is usually stored in the brain for up to a second and ensures that people can remember the sensory information even after the stimuli has been removed. This is maintained for a short period of time before some of the more significant details are transferred to the short-term memory. Since you are constantly taking in huge amounts of sensory information every moment, it is difficult to remember everything that you see, hear or smell, so information is lost in most cases.

Short term memory allows information to be stored for slightly longer, from 15 to 30 seconds. Based on an experiment carried out by George Miller, it was suggested that people could only store between 5 and 9 items within the short term memory, with information only being stored for a limited amount of time which can be lost quicker from other distractions. Since short term memories are stored for only a small period, it can easily be replaced with other items and information. It is stimulated mainly within the frontal lobe of the cerebral cortex.

Long term memory is where information is stored for the longest period of time and can be recalled after hours or years. It is usually not within our conscious mind and is only brought into our awareness when necessary. They can also be of different significance, and this will cause how easy these memories can be recalled to vary.  As we all know when revising for exams, memories that are recalled more frequently become stronger and of greater importance, reducing the time taken and making it easier to remember.  This is due to the strengthening of the neural networks, as they become stimulated more often.  When a memory is accessed within the cortex and hippocampus, the information is recoded by another set of similar neurones. As a result, this can affect the state of the memory, causing subtle changes and making certain parts of the memory stronger or weaker based on which neurons are activated.


Having some similarities to having a photographic memory, hyperthymesia, also known as highly superior autobiographical memory, is a condition in which the person can remember everything in great detail, including the majority of the experiences within their life. This may include the exact dates in which a conversation took place, regardless of its insignificance or a person they may have met 20 years ago. With only 61 people in the world having identified to have hyperthymesia, it is a very rare condition that can completely affect their lives. As they can never forget some of the experiences, some of the common traits they may suffer from includes spending long periods of time thinking about the past, and being able to concentrate deeply about these memories that they lose focus on things around them. Sometimes, this may put them in danger or just a lot of stress, as they are always absorbing and storing so much information at once.

Unfortunately, there have been no clues within brain scans in which to why they can store memories so well in comparison to normal people. However, a recent study showed that 20 people with HSAM scored highly on two sorts of tests: Fantasy proneness and absorption. Fantasy proneness is the process in which the person will be deeply involved in fantasising and daydreaming. Absorption is the ability for the person to concentrate fully within a certain situation and paying close detail to everything within that experience such as sensation. This means that strong links and very detailed experiences can be established during absorption, making it easy for it to be recalled when necessary and fantasy proneness allows these memories to be revisited every once in a while, making them stronger.

While there are benefits with being able to remember everything, there also are also some consequences. Jill Price, the first person to be diagnosed with HSAM, describes how she “hated” school, saying how she could not forget any painful, or embarrassing memories and how these unwanted memories would always be within her consciousness vividly. This can be mentally exhausting, and as a result many diagnosed with HSAM go through special treatment with doctors to learn to focus only on the good memories.


  1. Psychology Today “Memory” [online]
  2. Simply Psychology (2009) “Short term Memory” [online] <>
  3. Verywell mind (2020) “Long term memory types, duration and capacity” [online] Accessed 09/03/2020 <,is%20a%20long%2Dterm%20memory.>
  4. BBC Future (2016) “The blessing and curse of the people who never forget” [online] Accessed 26/01/2016 <>
  5. Healthline (2017) “What does it mean to have hyperthymesia or HSAM? [online] Accessed 25/05/2017 <>


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