The names of famous people in history or science, or the dates they did something notable, are the kinds of information that we keep in explicit memory. This type of explicit memory is called semantic memory.
We use our semantic memory all the time. Remembering the names of band members or the definition of a concept in science class are all kept in semantic memory. Explicit memory also includes memory of events and experiences. This type of explicit memory is called episodic memory. Remembering what happened at a store while shopping is an example of episodic memory.
Definition of Explicit Memory
Explicit memory involves the long-term storage of information (it’s sometimes called declarative memory).
When we read a book or study for a test, we are trying to put declarative information in our long-term memory.
Once that information is stored, it can be used later to answer a teacher’s question during class or write an essay on a test.
The key thing to know about explicit memory is that it takes mental effort to use.
For example, to answer a question from the teacher, you have to search through your long-term memory to find the information. After it has been found, then it has to be retrieved and placed in working memory. When it is in working memory, it can be used to answer the teacher’s question.
That all takes a lot of mental effort.
In technical terms, we say that it requires a lot of cognitive capacity. Cognitive capacity is kind of like the RAM on a computer. It’s how much information we can think about at one time.
People can only think about a limited amount of information at any one time. That is, people have limited cognitive capacity.
Explicit Memory Examples
- Remembering an old phone number: The digits of the phone number are stored in semantic memory. To recall the number, a person must search through their long-term memory, find the numbers, and then retrieve them one by one or in chunks.
- The first day on the job: This is an example of episodic memory. Remembering what the boss said or any stressful events that happened can almost be replayed in memory like a short video clip.
- Remembering the time of a doctor’s appointment: The time and date of an appointment is the type of factual information that is stored in semantic memory. When recalling the information, it requires a search and retrieval process. Once retrieved, the information will be moved to working memory.
- Going on a first date: Although the stress of a first date might make it hard to remember, some details can be retrieved. Opening the door and seeing their reaction to what you were wearing, what they said, how your parents reacted, are all details stored in episodic memory.
- Writing an essay on an exam: While writing, a student must recall key facts about the subject and important definitions. That information has to be retrieved from semantic memory. If the student studied enough, then the information will have been committed to long-term memory and easily retrieved.
- Falling off a boat: Most likely this is a flashbulb memory. It was a dramatic event, highly personal, and unusual. When something dramatic like this happens the visual features of it can be very detailed, almost like seeing a picture of the event itself, as if it were a photograph.
- Recalling the items on a shopping list: The list is stored in semantic memory. To recall each item requires cognitive capacity to conduct the search and then retrieve each item on the list. Most likely, after the information is used, it will be discarded from long-term memory because it is no longer needed.
- Describing a video to a friend: This episodic memory involves remembering what the different people in the video were doing, what they said, and what happened sequentially scene-by-scene. When describing it to a friend, it’s almost as if the video were playing in one’s mind.
- Memorizing the systems of the human body: This information will be stored in semantic memory. It includes the name of each system, the key components, and the primary functions of each system. To use this information requires the conscious search and retrieval of each detail.
- What happened on vacation: This is an example of episodic memory because it involves an experience. The memory could include the sights along the way to the vacation spot, the different activities everyone participated in, and any unusual events that occurred.
Key Processes in Explicit Memory
The first stage of memory is called acquisition. This is when we first encounter information. As we read the words in a book, we are thinking about the concepts, what they mean and what the sentences are telling us.
This all occurs in our working memory. Ultimately, if studying for a test, we want to transfer that information in our working memory into long-term storage. When it is placed in long-term memory it can be used later.
In order for this to happen, we have to be paying attention during the acquisition stage. This is a key requirement. Although that seems obvious, have you ever found yourself reading a book and all of a sudden realize that your mind is actually thinking about something else?
Even though it seems like we are reading and processing the words on the page, most of our cognitive capacity is being used daydreaming.
The second stage of memory is called consolidation. Once information has been transferred from working memory to explicit memory, it is stored in the brain.
Each piece of information stored creates a change in specific brain cells, called neurons.
The more times we rehearse a piece of information, the stronger the changes in the brain become.
More specifically, at the end of neurons are synapses that contain different chemicals (called neurotransmitters). The synapses of neurons are connected to each other (not exactly connected, but very close to each other; there is a small gap between them).
As you rehearse information, the synapses form stronger connections with each other. This is what makes a memory strong and therefore easy to remember.
So, if you are taking a test and having difficulty remembering a key fact, it’s because that fact is not stored strongly enough in your brain. The connections between the synapses that are associated with that fact are too weak. In other words, you should have studied a little more.
Retrieval refers to pulling information out of long-term memory. It actually starts with a search process. Once the information has been located, you can then pull it into your working memory and use it.
This means you can write the answer on a test or answer a teacher’s question. Unfortunately, in order for retrieval to work, that information has to be there.
If your studying was ineffective, and the information was not stored by changing those neurons, then it cannot be retrieved. It’s simply not there.
There are things a student can do to improve storage and retrieval. For example, it is easier to retrieve information if you are in the same or similar environment to when it was studied. So, studying in a classroom will make it easier to retrieve when in a classroom.
Sleeping well also helps. When we sleep the neural connections grow stronger. When those connections are stronger, then the information is easier to retrieve.
Types of Explicit Memory
1. Episodic Memory
Episodic memory is our memory of events and things that we experience. It is sometimes called autobiographical memory.
Experiences like conversations we had with friends or what happened at a concert are kept in episodic memory.
Episodic memory can contain a lot of detail. For example, if remembering a conversation among friends, some people can remember exactly what each person said, how they said it, and even what kind of facial expression they showed.
One type of episodic memory is called a flashbulb memory. This is a very vivid memory of an event that had a lot of personal meaning. For example, remembering where you were when you found out that your grandmother passed away is a flashbulb memory.
The memory is stored like a picture. It is very visual, and sometimes stored like a short video clip.
Sometimes dramatic news events can create a flashbulb memory. For example, when first learning about the assassination of a president can create a flashbulb memory.
See Also: Examples of Flashbulb Memories
2. Semantic Memory
Semantic memory is the type of explicit memory that stores knowledge about the world. This includes definitions of concepts, historical dates, and the names of people, places and things.
Theoretically, there is no limit to how much information a person can store in semantic memory. In technical terms, we say that semantic memory has unlimited capacity.
Of course, sometimes a memory will fade or decay. This might eventually lead to forgetting a definition or the meaning of a concept.
Trying to store information in long-term memory can also be disrupted through proactive interference and retroactive interference.
Proactive interference is when it is difficult to learn new information because of older information. Retroactive interference is the opposite. It is difficult to remember previous information because new information is interfering.
There are several factors which affect how long information stays in semantic memory. Generally speaking, repeatedly studying the same information is a good strategy to commit it to long-term memory.
Brief History of Explicit Memory
One of his most influential insights was to make a distinction between semantic and episodic memory, stating that:
“One system can operate independently of the other,” and most likely are “governed at least partially by different principles” although both systems are “closely interdependent and interact with one another virtually all the time” (1983; p. 66).
Even though he made those statements nearly 50 years ago, it turns out he was right. Semantic memory and episodic memory are independent, but a lot of time they also work together simultaneously.
For example, when remembering what happened on a vacation (episodic memory), a person will also remember key facts (semantic memory) such as the name of the vacation spot and who went along.
Explicit memory is our memory of facts and experiences. When talking about remembering the definitions of concepts or a list of items we need to buy at the store, that’s called semantic memory.
If remembering things that happened on a vacation or what people said to each at a social event, that’s called episodic memory.
There are three key stages of memory; acquisition, consolidation, and retrieval.
Acquisition refers to the process of receiving information; thinking about it in our working memory and then trying to transfer it to long-term memory.
Consolidation refers to how the information is stored in long-term memory. Changes in the brain’s neurons become stronger with time, especially during sleep.
Retrieval refers to searching for the information in long-term memory and then pulling into working memory. Once in working memory it can be used to talk about something or write an essay.
Eichenbaum, H. (2001). The hippocampus and declarative memory: Cognitive mechanisms and neural codes. Behavioural Brain Research,127(1–2): 199–207. doi: https://doi.org/10.1016/S0166-4328(01)00365-5
Gabrieli, J. & Kao, Y. (2007). Development of the declarative memory system in the human brain. Nature Neuroscience, 10(9), 1198–1205. doi: https://doi.org/10.1038/nn1950
Squire, L.R. (2004). Memory systems of the brain: A brief history and current perspective. Neurobiology of Learning and Memory, 82(3), 171–177. doi: https://doi.org/10.1016/j.nlm.2004.06.005
Tulving, E. (1972). Episodic and semantic memory. In E. Tulving & W. Donaldson (Eds.), Organization of Memory, (pp. 381–403). New York: Academic Press.
Tulving, E. (1983). Elements of episodic memory. New York: Oxford University Press.
Tulving, E., & Markowitsch, H. J. (1998). Episodic and declarative memory: Role of the hippocampus. Hippocampus, 8(3), 198–204. doi: https://doi.org/10.1002/(SICI)1098-1063(1998)8:3%3C198::AID-HIPO2%3E3.0.CO;2-G
Tulving, E. (2002). Episodic memory: From mind to brain. Annual Review of Psychology, 53, 1–25. doi: https://doi.org/10.1146/annurev.psych.53.100901.135114
Solso, R. L., MacLin, M. K., & MacLin, O. H. (2005). Cognitive psychology. Auckland: Pearson Education New Zealand.
Appendix: Description of Image
Top Level Heading: Long-term Memory
Sub-Category 1: Explicit Memory (conscious effort)
Types of Explicit Memory: Semantic Memory (facts and general knowledge) and Episodic Memory (events and experiences)
Sub-Category 2: Implicit Memory (without conscious effort)
Types of Implicit Memory: Procedural Memory (motor skills) and Priming (enhanced activation)