When you’re designing learning experiences, long-term memory is the ultimate destination. It’s the promised land—where you want newly learned skills and information to integrate with a person’s network of knowledge. So shouldn’t we be more familiar with the characteristics and dynamics of long-term memory? I think we need a user’s guide.
Overview of Long-term Memory (LTM)
- Long-term memory is a hypothetical construct. You won’t find a matching structure in the brain. But it’s helpful to think of long-term memory as a dynamic yet permanent store of information.
- Researchers have found regions in every lobe of the brain that store and retrieve memories of facts and events.
- We are usually referring to long-term memory when we talk about remembering something.
- Long-term memory encompasses three operations: encoding, storage and retrieval. These are explained below.
- It’s not just an archive of information and knowledge. LTM provides the wealth of information that we need to understand the world by bringing relevant knowledge into working memory as it’s needed.
Types of Long-term Memory
- Cognitive psychologists think of long-term memory as divided into two broad types. Explicit memory, also called declarative memory, refers to our conscious memories. Implicit memory, also called non-declarative memory, is unconscious. It consists of memories below our conscious awareness.
- Explicit memory (the conscious kind) can be theoretically organized into two types. Semantic memory refers to facts and knowledge about the world. Episodic memory refers to the memory of personal experiences.
- There are several types of implicit memories (the unconscious kind). Most relevant to training is procedural memory. This is our memory for doing things that usually require action. When we use a mouse on the computer or enter a phone number we are not consciously aware of the memories that enable us to perform these skills.
Capacity, Duration and Speed
- No one knows how long information can last in long-term memory. The duration could be indefinite. Think of the older people you know who are experts in their field or who remember details of their childhood. Some information appears to last forever.
- It is equally unknown how much information long-term memory can store. In practical terms, long-term memory seems to have an infinite capacity because it never gets used up.
- The time it takes to access information in long-term memory is thought to be 200 milliseconds or .200 seconds.
- Compare the capacity and duration to that of working memory. It’s quite different!
Encoding to LTM
- Encoding is the process of transforming information to store it in long-term memory. There are varied strategies that instructional designers and learners can use to improve encoding. See the Strategies below.
- Information in long-term memory is most likely stored in network-type structures called schemas. Schemas are an efficient way to organize interrelated concepts in a meaningful way.
- When we learn or experience something new and connect it with previously stored information, the process is known as assimilation.
- Sometimes we learn something new or have experiences that don’t fit in with existing schemas. We then alter existing schemas or create new ones in a process cognitive psychologists call accommodation.
Retrieval from LTM
- Retrieval is the process of activating and using information from long-term memory. A retrieval cue is any stimulus that helps us recall information from long-term memory.
- Some cognitive psychologists think that not being able to remember something is more a failure of not having the right cue than the fact that the information is not present in long-term memory.
- Recognition memory is almost always better than recall. Recognition involves determining whether you’ve seen something before. With recall, you have to generate the remembered information.
- Memories are more than a simple construction of recalled information. Rather, attitudes, beliefs and previous experiences influence what we recall. Memories are reconstructed events.
Strategies to Enhance Encoding and Retrieval
Learning experience designers can use strategies that enhance encoding and retrieving information and skills, as explained below.
- Use elaboration strategies to facilitate the transfer of information into long-term memory. Some elaboration strategies include: thinking of related ideas or examples of the content, mentally tying the information together or creating a mental image of the information. Course designers and instructors can encourage this behavior.
- Use the same type of elaboration for encoding that learners will need for retrieval.
- Make purposeful connections and associations with prior knowledge to improve transfer to long-term memory.
- Organize information by categorizing it into subsets to facilitate storage and retrieval. Many people do this spontaneously and instructional designers spend a great deal of effort at organizing information into meaningful chunks.
- Provide distributed practice across multiple study sessions rather than concentrating the same amount of practice into one session. This allows information to consolidate into memory over time, improving retention.
- Help learners associate facts with a personal experience to improve recall. Pairing semantic memories with episodic memories facilitates learning.
- Gagne, Ellen. The Cognitive Psychology of School Learning. Allyn & Bacon, 1997
- Goldstein, E. Bruce. Cognitive Psychology: Connecting Mind, Research and Everyday Experience. Wadsworth Publishing, 2010.
- Sternberg, Robert J. Cognitive Psychology. Wadsworth Publishing, 2011.
- Smith, Patricia L. and Tillman J Ragan. Instructional Design, Wiley, 2004.