Encoding Information to Make Memories
Have you ever thought about the incredible job our brain does every day, registering what is going on around us through our senses, filtering out the bits of information that are irrelevant to us and encoding the important items into memories? It is an incredible process and researchers don’t have the full picture as there are still processes we don’t understand.
The First Part of the Process
The first part of the process in making a new memory is encoding. This is the process that allows what we perceive through our senses to be converted into a construct that can be stored and later recalled from short or long term memory. A memorable event causes the neurons in our brains to fire more frequently. We know this from scans that show patterns of brain activity in bright colours. Emotion increases our attention and thus makes this activity even more intense. For instance seeing a loved one arrive after a long absence will probably make your neurons fire more excitedly than seeing your daily bus pull into the stop so you are more likely to remember your loved one’s home coming than how you yourself got home from school. The thalamus, frontal lobe and amygdala are the crucial parts of the brain for this initial process.
The Second Part of the Process
The perceived sensations are decoded in the various sensory parts of the brain and then combined in the hippocampus into one experience. The hippocampus then determines if this experience is to be committed to long term memory. It compares new experiences with previous ones and builds up associations. The various associations are stored in different parts of the brain. We don’t know much yet about how exactly this works but we do know that the hippocampus is crucial to creating memories as famous amnesiacs such as Clive Wearing, who have lost or damaged their hippocampus, lose the ability to make new long term memories and are forever trapped in the initial sensory mode.
We remember new things best if they mean something to us and can be associated with something we already know. We can build on this through a process of elaboration and students do this all the time, using mnemonics or mental imagery such as the ‘memory palace’ to remember crucial points for exams. Associations also work in reverse when it comes to memory retrieval. If you are always accustomed to listening to a particular kind of music while studying you may have trouble recalling that information in the silence of the exam room but may remember it all when next you play the same music. The message there is that if you have to remember something in a particular context, it makes sense to learn it in the same context so don’t play music when studying for exams!
Our most vivid memories of autobiographical events tend to be emotional. We will remember our wedding day, our child’s birth or baptism, the day a loved one died and so one in far greater detail than the routine everyday events that happen to us. This is for our own protection as if we remembered every single thing that ever happened to us on a daily basis we would be completely overwhelmed. This is what happens to people with a rare memory disorder called HSAM or Hyper Superior Autobiographical Memory or Hyperthymesia. Interestingly while they remember virtually every single thing that has ever happened to them, it is only their autobiographical memory that is affected so they are no better at passing exams than the rest of us as their semantic memory is unenhanced.
An interesting aspect of the emotional aspect of memory encoding is that if we are exposed to a highly emotional situation we may only have a very narrow recollection of that event as only the most important or significant part of the event is encoded in detail. For instance, people who have been caught up in a violent crime may only remember the weapon in detail as that is what they were focussed on and may not be able to recall the clothes their assailant was wearing or details of the vehicle he was driving. This is referred to as ‘weapon focus effect’ and explains why several different people witnessing the same event may give very different accounts of what happened.
Encoding is only the first part of making memories. The other stages are memory consolidation, memory storage and memory recall or retrieval which we will cover in separate articles. Each of these is important in that if there is any disruption to any of these stages, we can experience memory loss or amnesia in some form or another.