The Importance Of Semantic Memory

Semantic memory: Key insights into human brain function

Human memory is one of the most studied and complex fields in cognitive psychology, cognitive neuroscience, and psychological science. Despite decades of research, scientists are still striving to fully understand how the neural correlates of memory and the mechanics of how the human brain stores and retrieves information, particularly the differences between implicit vs explicit memory, and factors such as priming memory continue to play a significant role in this complex process. Researchers have, however, been able to determine several broad categories of memory, each of which plays a different role and relates to a different area of the brain. One of these categories—semantic memory—has been especially well studied because of its importance in daily functioning. Read on to learn more about what it is and what has been learned about how it works.

The basics of memory formation and knowledge retention

First, it can be helpful to understand the basic mechanics of how memories are formed. Memory is one of many cognitive processes that are part of the central nervous system. The formation of memories takes place within the medial temporal lobe and includes three broad stages: encoding, storage, and retrieval. 

• Memory encoding is the process through which we move information from short-term memory to long-term memory. If you've ever been introduced to someone and forgot their name moments later, chances are you got distracted so that the name was never encoded into information that your brain intended to retain.
• Memory storage is primarily the responsibility of the hippocampus, which forms and indexes memories for later use. Over time, well-established memories move slowly from the hippocampus to the neocortex—the outermost surface of the brain involved in high-order functions like sensory perception, language, and spatial reasoning.
• Memory retrieval is the method through which memories are tapped and strengthened. The more a specific memory is recalled, the stronger it becomes—which is why memory retrieval is an important part of ongoing memory formation. One example of this is academic studying techniques that involve repetition because repeated retrieval of facts and figures makes it more likely that those pieces of information can be recalled at will. Note that memories have an initial strength assigned to them by the amygdala, meaning those that carry more emotional weight are stronger and more easily recalled than those with a small or no emotional component. 

Types of memory 

There are several different types of memory, ranging from retention that lasts only a few seconds to information that an individual can recall at will over the course of an entire lifetime. These types are organized into two broad categories: short- and long-term. Within long-term memory, there’s also implicit and explicit memory, with the latter then being divided into semantic and episodic memory.

Short-term memory

Short-term memory refers to anything that the brain holds temporarily. Generally, when a person refers to memory or "remembering something", they are referring to long-term memory, not short. Short-term memory is an essential component of processing information, but the ability to recall learned information comes from long-term memory.

Long-term memory

Long-term memory is split into several sub-categories, each representing a separate brain circuit for remembering certain information over time. The broadest categories of long-term memory are implicit memory and explicit memory, both of which are broken down into additional categories as outlined below.

Implicit memory

Implicit memory, or non-declarative memory, is associated with memories that were obtained subconsciously, without the individual’s awareness. Implicit or unconscious memories can either be procedural or the result of priming.

Procedural implicit memories involve learned motor skills. Tasks that require "muscle memory" are usually guided by procedural implicit memories, for instance, such as riding a bike or typing on a keyboard. Priming, on the other hand, involves using one unconscious memory to influence the evaluation of another. For example, an individual participating in a word-judging task is likely to identify associated words (such as BREAD-BUTTER) more quickly than unassociated words (BREAD-DOCTOR). This is because these words are semantically related and the association has been "primed" in the person's memory, allowing for faster recall.

Explicit memory

Explicit memory, or declarative memory, is connected to memories that were formed consciously and associated with the context of a particular place, time, feeling, etc. It’s further split into two categories: episodic memory and semantic memory.

Episodic memory

Episodic memory refers to what most people think of as "memories". Sometimes called autobiographical memory, these memories contain information about past experiences, such as a recent conversation with a coworker, dinner with a friend, or where you parked your car. A person reminiscing about a fun activity they did on vacation last year is also using their episodic memory to recall the images, sounds, themes, and emotions associated with the event. Episodic memories are linked to the specific time and place the event occurred.

Semantic memory

The other category of explicit memory is semantic memory. Semantic memory refers to retaining general knowledge about the world such as functional and perceptual features of things we encounter along with other general facts we may associate with them. Semantic memory primarily takes place in the anterior temporal lobes. Semantic memories are associated with conceptual knowledge of the world and aren’t typically associated with a specific event. Semantic memory allows us to link word meanings to pieces of knowledge, meaning that it’s a key component in our ability to describe things we’ve seen or experienced.

Episodic vs. semantic memory

To understand the difference between episodic and semantic memory, consider the example of someone who recently took a trip to the zoo. If you ask the person to picture the trip in their mind, they will likely be able to close their eyes and conjure up a mental image of the zoo and the animals they saw. If you ask the person to tell you about their trip, they would likely be able to describe the animals and other features of the place. When picturing the zoo in their head, they’re relying primarily on episodic memory. When describing the zoo to you and naming the animals they saw, they’re relying on world knowledge – which is semantic memory – to assign verbal descriptions to their experiences.

In practice, episodic and semantic memory are two sides of the same coin. The average person carries out both semantic and episodic tasks in day-to-day life, and both semantic memory and episodic memory involve important parts of retention and recall. They are handled by different parts of the brain, but they can function both independently and interdependently.

Researchers in one study discovered that patients with dementia whose use of one type of memory was severely impaired often retained full use of the other type. However, studies have also found that “semantic memory facilitates the acquisition of new episodic memories”, and that “episodic memories facilitate the retrieval of information from semantic memory”. In other words, episodic and semantic memory are important for optimal functioning.

Tips for improving semantic memory using episodic memory

The act of improving semantic memory goes by another name that the average person may be more familiar with: studying. While episodic memory is an automatic process that happens unconsciously, improving semantic memory – and the organization of semantic memory – requires concentration and effort, but it is possible. There are strategies other than the repetitive reviewing of information, however, that can be more effective when it comes to improving semantic memory and processing.

The memory palace memorization technique, also known as the Loci technique, is one such strategy. It involves leveraging your episodic memory to bolster your semantic memory. Here’s how you might go about using this method to retain facts or concepts: 

1. Pick your palace. Think of a place familiar enough to you that you can imagine walking through the entire area, such as your childhood home or your workplace. The route you use to walk through the structure in your imagination should be the same every time you "visit" your palace. Sketch out a floor plan that details the linear route you’ll walk. 
2. List distinctive features. Look for distinctive features, objects, or points in the structure, like furniture or hallways, for example. Give each of these features a number on your floor plan according to the order in which you’d see them as you walk your route.
3. Associate memories with features. Associate a piece of information with each feature you’ve identified along your route. It can be especially helpful if you’re able to find some commonality between the feature and the piece of information you are trying to memorize. 
4. ‘Walk’ through the palace. In your mind's eye, walk through your mind palace and notice each feature you pointed out. The association between your episodic memory retrieval of the feature and the semantic concepts you are trying to memorize should make the semantic information easier to recall.

Semantic memory can also be improved through simpler memory strategies such as concept linking, mnemonics, self-testing, and interleaving. A key point to remember is that any improvement in your semantic memory system will require effort and dedication to practicing.

How therapy can help with semantic memories and other memory challenges

Meeting with a therapist can be helpful for people experiencing challenges related to semantic memory (or other memory challenges). For those who have been diagnosed with semantic dementia or other related cognitive problems, therapy can help them cope with difficult emotions they may be experiencing related to their condition. For those whose daily functioning is negatively impacted by traumatic past memories, therapy can help them address these and develop healthy coping skills. For those who are struggling with memory as a symptom of a mental health condition like depression, therapy can help them address these as well.

If you are experiencing trauma, support is available. Please see our Get Help Now page for more resources.

The benefits of choosing online therapy

In many cases, virtual therapy can be as effective as in-person therapy. If you’d prefer to meet with a therapist online from the comfort of home rather than traveling to an office for each appointment, you might consider a virtual therapy platform like BetterHelp. You can get matched with a licensed therapist who you can meet with via phone, video call, and/or online chat to address the challenges you may be facing. Many people appreciate the convenience and cost-effectiveness of this therapy format in comparison to traditional, in-office sessions. However, since either format can be helpful for those experiencing memory issues or a variety of other mental health concerns, you can typically choose the one that feels right for you.