Written by Gurleen Khaira
Commonly, you hear the word ‘memory’, and think of a fond moment from a while ago. Whilst this is one type of memory, there are others too. There are some memories we do not even know we had since our brain did not register them, whilst others which only last for a few seconds. So, we decided to investigate the three types of memories we have: sensory memory, short-term memory, and long-term memory.
Every second, you are exposed to numerous stimuli in your environment. From multiple background noises, to different smells, our brain takes in huge numbers of stimuli. However, not all of these are realised. These numerous stimuli are sensory memory and only last for a maximum of 3 seconds. After this, only those stimuli that are deemed relevant through conscious effort are registered in short-term memory. There are three types of sensory memory:
Iconic memory- this refers to all visual stimuli, so everything you see. This lasts between 0.25-0.5 seconds
Echoic memory- this is auditory sensory memory, so everything you hear. This lasts for around 3 seconds
Haptic memory- this is the memory of touch, and lasts for around 2 seconds
Short-term memory, also known as working memory, is the memory of what you are currently doing and concentrating on. Short-term memory can hold around 7 pieces of information at one time. Incoming information pushes out old information by a process known as displacement. Normally, this type of memory lasts between 10-15 seconds, but can be extended up to a minute in some situations. To keep information in the short-term memory for longer, rehearsal can be used, where you repeat the items to be remembered numerous times. Chunking can also be used. This is a process where large pieces of information are broken down into smaller, related groups, making it easier for the brain to remember.
Long-term memory refers to anything that you remember for more than a few seconds, to some of your earliest memories. Three types of long-term memory are: