Hiking Through Hell Valley: Episodic vs. Semantic Memories

Let me tell you a short story. After you read it, see how many details you can recall.

In the summer of 2013, I embarked on a grand adventure. I traveled halfway across the globe to Sapporo, Japan, which is home to the ramen noodle. From there, I took a train to Hell Valley where I hiked up the side of a mountain. Midway though the hike, me and my three friends stopped to soaked our feet in a 110-degree mountain stream, which was fed by a hot spring.  We also saw wasps the size of your thumb. When we got back to Sapporo, we went out to dinner, sat on the floor, and ate sushi made from yellow-fin tuna.

Now take a few minutes to repeat back my story with as many details as you can recall.

• What details did you omit (or insert)? 
• Which parts were the easiest (or hardest) to remember?
• Were you able to get the chronology right?

Thirty-one Flavors of Memory

My little story might leave an impression, but I guarantee that you will remember it in much more detail, and for a longer period of time, if it actually happened to you.

This demonstration is meant to underscore the fact that we have the ability to learn vicariously from other people. We can also learn from our own histories and from our own autobiographical memories. The memories that we create directly from our experiences are called episodic memories. These memories are like own own personal narrative. They consist of an event that takes place in a particular time and place (i.e., the "setting"), and potentially with other people (i.e., the "characters"). They might also contain an emotional element (e.g., laughing with your friends when you discover how incredibly hot the hot springs truly are). 

Episodic memories are often contrasted with semantic memories, which don't really have a personal connection to your life. Reading about my trip to Japan results in a semantic memory for you, but it is an episodic memory for me. Because semantic memories are not tied to a specific time or location, they are general knowledge about the world. This might sound familiar because both episodic and semantic memories are different subtypes of declarative memory.

Is the distinction between episodic and semantic memories real, or is it merely a convenient theoretical distinction? There is suggestive evidence from neuroscience that these two types of memories are represented in different areas of the brain. For example, individuals who have damage to the hippocampus or left prefrontal cortex lose the ability to form new episodic memories; however, their ability to learn new facts is left (mostly) intact.

The STEM Connection

How does this connect to education? A large percentage of information that a student must learn is semantic. In the end, we want students to remember facts like: plants take in carbon dioxide and expel oxygen. Moreover, we want our students to remember the lessons that they learned in school for a very long time. It is probably a stretch to expect our students to remember everything we teach them; however, given our knowledge about the way memory works, we can structure information in a way that resonates with the brain.

When something is personally relevant, it is easier to learn and remember. As we saw earlier, memories are easier to retrieve when we have multiple routes to that information. It's also the case that our semantic network is densely packed with information about our own lives. Thus, if we can embed scientific, technological, engineering and/or mathematical information in the context of our lives, then it is likely that we will own that information. 

The challenge for instructional designers is to figure out a way to make STEM lessons come to life. One potential method is to make lessons more like episodic memories and less like semantic memories. We could teach kids a strategy for mental arithmetic. That would provide the students with a strategy that will be devoid of any episodic memory. Alternatively, we can ask students to work in small groups to invent their own a strategies [2]. If they attempt to solve this on their own (with sufficient scaffolding and resources, of course), then the event itself will become part of the memory. They will remember working with other students, in a particular context, and maybe even remember some of the wrong avenues they explored and how they were able to overcome those obstacles. 

Ultimately, the goal is to help students bind content knowledge to the vast repository of other episodic memories. Asking students to invent their own strategies is immensely gratifying, and it can serve as potential gist for long-lasting, personal memories. To conclude, I will leave you with this quote from Benjamin Franklin:

   Tell me and I forget,
   teach me and I may remember,
   involve me and I learn.

Share and Enjoy!

Dr. Bob

For More Information

[1] Tulving, E. (1972). Episodic and semantic memory. In E. Tulving and W. Donaldson (Eds.), Organization of Memory (pp. 381–402). New York: Academic Press.

[2] Schwartz, D. L., & Martin, T. (2004). Inventing to prepare for future learning: The hidden efficiency of encouraging original student production in statistics instruction. Cognition and Instruction, 22(2), 129-184.