Memories: Episodic and Semantic Memories
As I get older, I’m having a harder and hard time remembering things. For example: I don’t remember what I ate for breakfast two days ago, I don’t remember what I covered in my psychology class last week, and I definitely cannot remember the great lakes of Canada.
My memory is becoming more and more important to me as I’m advancing in University. Especially since everything you learn has to be stored in your brain if you want to pass with good grades. However, I noticed something that was often discussed with my other classmates following final examination periods. The tendency to forget everything we learned the moment we finished the exam. Now this got me into reading a little bit about our memory and how it works. Specifically, I’ll be focusing on the semantic and episodic memories; memories of events and facts.
Episodic memories are autobiographical events that “ I remember”. They’re often memories one can easily communicate and is consciously accessible to us. It’s often tagged in both spatial and temporal context in our brains and is often learned in a single exposure.
Example: your 2nd birthday party, or the time you fell and scraped your knee
Semantic memories are factual events that “ I know”. Theyre often memories that can also easily be communicated and accessible. However, they’re not necessarily tagged spatially or temporally and even though they can be learned in a single exposure, repetition strengthens the memory. These memories are usually concerned with facts.
Example: the names of the provinces of Canada or your phone number
A question that has been debated for a long time concerning these types of memories is whether semantic and episodic memories interact? The answer has yet to be decided on, some research suggest that semantic memories are reliant on episodic memories while other research suggest the opposite. However, recently some research is even suggesting they are in fact distinct and that effects on either or shouldn’t effect the other. Ultimately, this question remains unanswered definitively.
So how are these memories stored? There are three steps to storing memories: encoding, consolidation and retrieval.
Encoding: is when you create the trace of the memory in your brain.
Consolidation: is when you store the trace of the memory
Retrieval: is when you recall or reactivate the trace of the memory.
There are certain factors that effect the strength of the memory at every level of memory storage.
During the encoding phase certain factors that may affect the level of encoding are:
Attention versus exposure
Simple repetition is not an effective way of encoding new memories
Association/links to existing memories
Related information must precede target information to
enhance recall
Information that is more deeply processed is encoded better
During the consolidation/ retrieval phase certain factors that may effect the level of encoding are:
Match between encoding and retrieval conditions
Retrieval works best when conditions are similar to encoding conditions
“transfer-appropriate processing” effect
The more cues that are provided, the easier it is to recall a memory
Sometimes memories fail, and certain factors in the retrieval phase that can affect this are: Forgetting, interference of other information,misattribution and false memories. Why and why do we forget? We essentially forget information within the first few hours to first few days of learning it. We can also intentionally forget information if we want to ( directed forgetting). These are a few theories that can explain why we forget.
Consolidation Theory: memory is solidified gradually after the encoding event
Trace Decay Theory: memory traces are eroded by the passing of time
Interference Theory: older memories become harder to retrieve because there is competition with other memories
New information, especially similar information to what has just been learned can also interfere with retrieval. Two types of interference are proactive interference and retroactive interference.
Proactive Interference is concerned with previously learned memories that affected newly learned memory.
Example: having trouble memorizing a new postal code after you’ve moved, you keep remembering your old one
Retroactive Interference is concerned with recently learned memories affecting retrieval of older memories.
Example: having trouble remembering your old phone number once you’ve had a new one for a while.
Other types of retrieval failures we may have been exposed to are Source Amnesia which is concerned primarily with forgetting where you obtained a certain memory or information from.
Example: Lucy told me about the new supermarket on St-Denis but I think that John told me about it instead.
Another type is cryptomnesia where someone’s idea is mistakenly attributed as your own.
Example: Even though my husband told me about going camping in the rocky mountains earlier in the year, I had forgotten he had told me and believed that it was my idea to do so.
False memories also affect retrieval of memories. It has been proven that our memories aren’t as reliable as we think even if we experience situation first hands. Different levels of manipulation at various steps of encoding information can be used to change the memory or falsify it either by us or by someone else.
Example: When a couple breaks up it is easy for each individual to create false memories about situations to benefit their character. Tommy remembers Elena being the one who broke the plate after the fight, while Elena remembers that she had dropped the plate by accident since Tommy was being so loud and aggressive during the fight.
Now to quickly answer the question that initially pushed me to write this post, “ why do i forget all the information I learn for my exams right after I’m done?” can be answered by the reconsolidation theory.
Reconsolidation Theory speaks about when memories are reactivated it is important that they are actively re-stored. Or else, the information is at risk of being lost, these old memories are fragile during the short window post-reactivation. So after our exams it is wise to review the material carefully one last time to make sure it is properly stored.