Take home message
- Memory can be divided into explicit and implicit memory.
- Explicit memory refers to the memory for events and things that happened in the past (episodic) as well as facts and worldly knowledge (semantic).
- Implicit memory allows us to perform actions without having to draw on our conscious memory. This explains how we can ride a bike and walk!
Let’s take a walk down memory lane and look at what types of memory there are.
Explicit Memory (aka Declarative Memory)
This is what most people have in mind when they talk about memory. Sometimes referred to as factual memory, it involves a conscious effort to remember something; a name, a face, what the capital of Egypt is. These are our explicit memories and they are also associative. That’s to say they work in networks which trigger each other. Say you’ve been reminded of an old friend from high school–suddenly, you’re off thinking about people you haven’t seen for years, remembering events and places as though they happened just yesterday.
Episodic memory: One category of explicit memory describes precisely this experience of remembering events. Episodic memory is autobiographical. It is memory of things which directly happened to us; such as the people present at our last birthday or the face of a loved one (or not-so-loved one).
Breakdown of episodic memory: When we forget the details of something that happened to us, this is usually a breakdown of episodic memory. We forget an appointment, can’t remember details from the meeting we attended yesterday, or how many coffees we’ve had to drink this morning. Needless to say, this can wreak havoc on our daily functioning and is a serious problem for many people.
Semantic memory: On the other side of explicit memory, we have things which we didn’t witness, but know nonetheless. We can recall that Cairo is the capital city of Egypt without having been there and we know that a kettle boils water; we just seem to know this information without knowing how or when we learned it. ‘Textbook’ learning is another common term for semantic memory, since it covers anything from concepts and ideas to facts and locations.
Breakdown of semantic memory: Semantic breakdowns can range in severity. A simple case might be forgetting the name of a famous musician. More seriously, it can result in being unable to recognise a written word, despite understanding it when you hear it. You might notice that when someone looks at a German Shepard they can’t quite find the name of it but might call it a dog, as their condition progresses and their semantic memory becomes worse they might become less specific and call it an animal.
Implicit Memory (aka Procedural Memory)
Perhaps the hint is in the name; unlike explicit memory, implicit memory seems to happen without our knowing.
Procedural memory: It may be difficult to imagine that we actually had to learn how to walk; but we did. Procedural memory lets us complete tasks without consciously drawing upon past experiences. We know how to ride a bicycle without reminding our legs of what to do, just as we know how to eat with a knife and fork, or type words on a keyboard. When we repeat an action so often that it comes ingrained in procedural memory, we have the sensation of being able to do it automatically.
Breakdown of procedural memory: Forgetting how to walk is not so common, but basic motor functions can often breakdown with procedural memory loss. A common example of this might be forgetting how to play a piece you once knew on the piano, or how to write with a pen if you’re always typing!
Difficulty remembering appointments or details of conversations is episodic; forgetting how to use a knife and fork is procedural; and that tip-of-the-tongue phenomenon is likely a case of semantic breakdown. By honing in on the specifics, we take away some of the frustration and mystery of forgetting. Understanding memory gives us a chance at identifying points of failure in everyday life and narrows down what strategies will be effective, thus making our treatment both efficient and effective. At the very least, we can say a little more about what is happening to us.