Episodic memory is a person’s unique memory of a specific event, so it will be different from someone else’s recollection of the same experience.
Episodic memory is sometimes confused with autobiographical memory, and while autobiographical memory involves episodic memory, it also relies on semantic memory. For example, you know the city you were born in and the date, although you don’t have specific memories of being born.
How episodic memories are made
Forming an episodic memory involves several unique steps, each of which involves a separate system of the brain. The first step in the process is called encoding, a process that your brain goes through each time you form a new episodic memory.
Another step in the process of forming an episodic memory is called consolidation, which is basically baking the event into your long-term memory. This helps the memory become more strongly ingrained so that it is not lost if the brain suffers an impairment. Episodic memory can be affected by trauma, hydrocephalus, tumors, metabolic conditions such as Vitamin B1 deficiency, and neurological diseases such as Alzheimer’s disease.
The final process involves recollection. Recollection is a process that elicits the retrieval of contextual information pertaining to a specific incident. Sometimes a recollection from long-term memory is retrieved almost effortlessly, and other times it may need something to trigger it, such as a word, an image or even a smell.
Examples of episodic memory
People are usually able to associate particular details with an episodic memory, such as how they felt, the time and place, and other particulars. It is not completely understood why we remember certain instances in our life while others go unrecorded in our episodic memories. It is believed that emotion plays a key role in our formation of episodic memories.
Some examples of episodic memory:
- Where you were and the people you were with when you found out about the 9/11 attacks
- Your skiing vacation last winter
- The first time you traveled by airplane
- Your roommate from your first year in college
- The details about how you learned of a relative’s death
- Fearing water because you were knocked over by a wave at the beach as a child
- Your first day at a new job
- Attending a relative’s 75th birthday party
- Neighbors on the block where you grew up
- The movie you saw on your first date with your wife
Semantic memory vs. episodic memory
Episodic memory and semantic memory are two major types of memories that make up part of your long-term memory; together they are known as declarative memory.
While episodic memory is an individual’s unique take on a particular episode — which will vary from the recollection of others who were at the same event — semantic memory is just the facts.
While a bride will recall the date that she was married — information that is not in question — her remembrances of the event are going to differ from those who attended the ceremony and even from those of the groom.
Researchers have noted that while these two forms of memory are separate, they do not necessarily operate completely independently. In 1972, Endel Tulving of the University of Toronto detailed the differences between episodic and semantic memory in his book, "Elements of Episodic Memory." He noted that semantic and episodic differ in how they operate and the types of information they process.
Tulving observed that forming a new episodic memory is affected by information in semantic memory. A memory must pass through the semantic memory before it can be cemented into long-term memory as an episodic memory.
Live Science newsletter
Stay up to date on the latest science news by signing up for our Essentials newsletter.
Kim Ann Zimmermann is a contributor to Live Science and sister site Space.com, writing mainly evergreen reference articles that provide background on myriad scientific topics, from astronauts to climate, and from culture to medicine. Her work can also be found in Business News Daily and KM World. She holds a bachelor’s degree in communications from Glassboro State College (now known as Rowan University) in New Jersey.