Our memory is what allows us to remember new information and retrieve old information in order to make sense of the world. Memory is the persistence of learning over time, involving the storage and retrieval of information. This process can be defined by three steps: encoding (new information enters our brains), storage (information being kept in the brain), and retrieval (information being remembered for later use).
In order to measure our retention of information there is recall, recognition, and relearning: all of which are used in our daily lives testing how much information endures in our long term memory. Recall is similar to a fill in the blank question, in which information must be retrieved without cues. In contrast, recognition is more similar to a multiple choice question where a certain stimuli can be matched to previous information. Lastly, relearning can determine how much one remembers because it takes less work to learn information you have studied before. According to Herman Ebbingaus, a pioneering psychologist in the 19th century, the more one rehearses information, the less time they will need to relearn it.
Stages of Memory
The human memory system can be explained with the Atkinson-Shiffrin three-stage processing model. In stage one, our senses take in stimuli which is held briefly in sensory memory. Sensory memories are made up of sensory stimuli, including iconic (visual), echoic (sound), and haptic (touch). Then in stage two, some sensory information is processed into short term memory, with the help of our working memory, which uses rehearsal, focus, and linking to create explicit memories. Specifically, the central executive, a brain function, drives memory by processing visual and auditory perceptions. The central executive retrieves information from long-term memory to help interpret new information. Lastly, in stage three, information moves into long-term memory. Sometimes, information can skip stage two due to automatic processes and forming implicit memories.
Implicit Memories vs. Explicit Memories
Implicit, or nondeclarative, memories are formed without conscious effort or recollection. This includes procedural memories for automatic skills, such as riding a bike or the meaning of basic words, as well as conditioned association, such as a smell triggering an emotion. With our two-track mind and automatic processing, information about space, time, place, and frequency can be understood.
In contrast, explicit, or declarative, memories require encoding and effortful processing. Firstly, we briefly capture a sensory memory of all the sensations we are experiencing. For echoic memories, which are auditory, we can remember the last three or four seconds of sounds even without paying attention. Our iconic memory allows us to make sensory memories with exposure to visuals as short as 1/26th of a second. Another type of explicit memory is short term memory, which has a capacity of seven bits of information at a time. Without rehearsal from our working memory, short term memory decays in about twelve seconds.
Levels of Processing
On the one hand, shallow processing means that we encode on a basic level, such as specific numbers of a word’s letters. At times, such processing is helpful when only wanting a surface level understanding or an interpretation of specific information. However, if memorizing larger or more profound pieces of information, deep processing, such as encoding based on the meaning of a word, is more important.
Due to the self-reference effect, we are more likely to encode information that relates to us, such as if someone’s name is the same as a family member’s name. Apart from using ourselves as references, there are many effortful processing strategies that help us from keeping memories from decaying and making retrieval easier. This includes chunking data into manageable units, mnemonics as memory tricks to connect information to imagery, and hierarchies to commit categories to memory. The keyword method is also an effective way to improve memory by inventing an image with key words that sounds like the word being memorized.
When memories are stored in our brain, they form overlapping and complex neural networks. Explicit memories, such as facts, stories, and specific experiences are encoded and stored by the hippocampus for a few days where they are consolidated. Afterwards, they are moved to other parts of the brain and are ultimately retrieved in the frontal lobes. This process explains infantile amnesia because the hippocampus is not fully developed prior to the age of three.
Conditioned associations, which are an example of implicit memories, are stored by the cerebellum, while the basal ganglie controls procedural/motor memories. Emotional memories are also stored in a unqiue way. When we are experiencing stress or heightened emotions, stress hormones are released, which trigger activity in the amygdala. As a result, the frontal lobe and basal ganglia tag memories as important so that they are unlikely to be forgotten.
Forming memories also impacts the neurons in our brains. When memories form, neurons release neurotransmitters across synapses, or the space between neurons, to other neurons. As the amount of activity in neural pathways increases, neural connections strengthen: a principle called Long Term Potential (LTP). Certain environmental conditions, like drugs and shocks, can affect LTP by increasing, decreasing, or erasing learning.
There are many things that can influence how well we can retrieve certain information. Part of the web of associations of a memory is the context, which is what else was occurring when the memory was being formed. Due to context-dependent memory, we can better retrieve memories in the same context as when they were formed. For instance, if one were to sit in a specific seat when learning the content for a test, they are more likely to retrieve the information better if sitting in the same seat during the test. A similar idea can be applied to state-dependent memory, in which memories can be tied to the emotional or physiological state we were in when the memory was formed. For example, mood-congruent memory causes us to selectively remember things that are consistent with one’s current mood. Therefore, if one is unhappy by their current situation, they will more readily remember past details of other negative events, perpetuating their bad mood. However, we do have a positivity bias, which means that we subconsciously process pleasant items more efficiently than unpleasant.
Another way that our memory is influenced is the order in which we acquire information. Due to the serial position effect, we are more likely to recall the first and last items of a last. Particularly, the recency effect means that we immediately remember the last item, while the primacy effect means that after some time we remember the first item best. Therefore, the order that we receive information is important to how well we remember it in the long run.
As frustrating as it may feel when we cannot remember certain information, there are many benefits to forgetting. This includes priortizing important memories, avoiding feeling overwhelmed by irrelevant information, and focusing on current stimuli without distraction.
One explanation for forgetting is that we fail to encode all the information we are exposed to for entry into our memory system. Without effortful processing, much of our external stimuli either goes unnoticed or unprocessed.
Additionally, amnesia explains how we may forget information. One type of amnesia is anterograde amnesia, in which we cannot form new long-term explicit memories. Oftentimes, this is caused by a severe brain trauma, surgery, drugs, or alcohol. Another type of amnesia is retrograde, which is the generally temporary inability to retrieve past memories, usually caused by head injuries or emotional trauma.
If memories are never used or recalled, storage decay of long term memories will occur. As demonstrated in Ebbinhaus’ forgetting curve, what does not decay in the short term, tends to stay in tact for a long time. Even if information is committed to memory, retrieval failures may occur if we have too few cues to help us remember non-decayed memories. This often leads to what is known as the tip of the tongue phenomenon when a memory feels like it is just below the surface but we cannot articulate it.
Interference can also prevent us from retreiving old information or learning new information. Firstly, retroactive interference occurs when new learning interferes with the retrieval of previously learned information. For instance, if a teacher begins a new unit before the previous unit’s test is administered, students’ new learning will interfere with their ability to remember the previous. In contrast, proactive interference occurs when past information interferes with learning new information, such as remembering a new password or address.
Sometimes, we may feel motivated to forget memories and choose to forget, change, or self-censor our memories. Sigmund Freud describes this process as repression, meaning that we subconsciously want to bury memories that bring us anxiety.
Errors in Memory
Oftentimes, the passage of time, the imagery of an event, or collective misremembering can influence our memory construction whether or not the memory is real. The misinformation effect occurs when we incorporate misleading or false information into our memory of an event. This usually occurs when the passage of time causes the memory to fade, and is most common in people under five and over seventy-five. Moreover, the imagination effect describes how just picturing an event can make it seem like a real memory. If someone were to help another recall a memory, it is possible to implant a false memory by how powerful imagining an event can be.
Source amnesia and missattribution commonly occur when we forget where a story comes from and attribute the source to our personal experience. For instance, we may believe that something happened in our childhood, but later find out that that event happened to a sibling or in a movie that was watched at the time. Another common occurrence is deja vu, when our sense of familiarity and recognition happens too soon, and our brain attributes this as being caused by prior experience. The Mandela Effect is also a fascinating phenomenon when a similar false memory is shared by multiple people, usually known as a cultural collective false memory.
Our memories are crucial in our everyday lives as we are constantly required to learn more information, while remembering the past. However, there is no need to worry if your memory is not up to standards because it can always be improved. By creating more retrieval cues, such as mnemonics, minimizing interference when studying, and doing distributed practice, you may find yourself doing better on tests or remembering necessary information more readily. Regardless, our memories are complex and dynamic aspects of shaping who we are and our everchanging view of the world.