Implicit memory is a type of long-term memory that refers to information that is remembered unconsciously and without effort. Even though it is retrieved without intention, implicit memory can still affect behavior.
Examples of Implicit memory include information for how to carry out tasks such as typing or riding a bike. When a person performs these tasks, they are using their implicit memory.
There is no need to exert any cognitive effort when trying to remember how to ride a bike; it just happens…without thinking. This type of implicit memory is sometimes called procedural memory.
Implicit Memory Definition
Restoring implicit information in your memory and retrieving it later on is a type of implicit learning. Below are two scholarly definitions of implicit memory:
- “Implicit memory refers to a change in behavior or performance that occurs as a result of prior experience without conscious recollection of that prior experience” (Glisky, 2017, p. 1)
- “Various types of perceptual, motor, and cognitive skill learning can also be considered expressions of implicit memory, in that they can occur without reference to, or recollection of, prior learning episodes” (Schacter et al., 1993, p. 160-161).
Implicit Memory Examples
- Making a phone call to a friend you call frequently.
- Speaking a second language after living in a foreign country for 10 years.
- Being in a bad mood and then remembering negative things that happened in your childhood.
- Doing routine tasks such as tying shoes or buttoning a shirt.
- Playing a game of solitaire, which has simple rules you are familiar with.
- When you start humming the tune to a song you have known since childhood.
- Walking through your old neighborhood and being flooded with memories.
- Giving a well-rehearsed lecture for the 17th time.
- When a college student reads a passage in a text but suddenly realizes they don’t remember any of the content.
- Hearing a song that you used to share with a romantic partner and then remembering the good times you had together.
Implicit Memory vs Explicit Memory
Implicit memory and explicit memory are terms used to explain two opposite memory functions in the brain.
- Implicit memory refers to unconscious memory that is built up through habits and acquired skills, such as the memory built from riding a bike as a child or the ability to type on a keyboard without thinking. It is also called non-declarative memory because it is not something that can be easily verbalized or put into words.
- Explicit memory, on the other hand, is the conscious memory of facts and events. Examples of explicit memory include remembering and recalling the memory of a person’s name, or the date of a historical event. Explicit memory is also known as declarative memory because it can be explicitly stated, or in other words, declared.
1. The Legacy of H. M.
A lot of what we know today about implicit memory comes from neuroscience. One case in particular, that of H. M., led to numerous insights about how memory functions are organized in the brain.
At the age of 10, H. M. began experiencing minor seizures due to a bicycle accident. The seizures became progressively worse until at the age of 27 he was unable to work or lead a normal life.
Patient H. M. was studied by neuroscientists for nearly five decades. He was administered an incredible array of memory tests and asked to do many types of testing.
For instance, one test required that he trace the outline of a star, but could only see his hand and star as reflected in a mirror.
He was able to master this task and perform it again 3 days after testing. “Yet at the end of testing, he had no recollection of having done the task before” (Squire, 2009, p. 8).
“The findings from H.M. established the fundamental principle that memory is a distinct cerebral function, separable from other perceptual and cognitive abilities…” (p. 6).
2. Priming and Memory Networks
The term priming in psychology refers to when exposure to a stimulus affects a person’s subsequent experience. That exposure can be so subtle that it is hardly recognized or not noticed at all. Because priming effects are outside of conscious awareness, it is considered a manifestation of implicit memory.
There are at least 10 types of priming and many of them can affect information stored in memory.
In long term memory, concepts are stored and interconnected. Concepts that are highly related have strong links to each other.
Priming one concept can increase the likelihood of other, related concepts being activated as well.
For example, the word “nurse” will be recognized far more quickly after being exposed to the concept of “doctor” than if exposed to a vastly unrelated concept such as “spaghetti.”
3. Procedural Memory
Procedural memory is a type of implicit memory that is activated when we are performing a well-learned task. Motor activities such as riding a bike or typing on a keyboard are examples of procedural memory.
Tasks that have been practiced repeatedly eventually become automatic, which means they are performed requiring very little attention or cognitive capacity.
As an illustrative example, when a person has practiced a particular song on the piano for an extended period of time, they can play it without “thinking.”
In fact, because they have rehearsed it so many times, they can think of other things while playing. This is what we mean by procedural memory requiring very little cognitive capacity.
Most people experience this phenomenon when driving to work. Because they have taken one particular route for so long, perhaps even years, their mind can drift away to ponder matters completely unrelated to driving.
4. Priming and Shopping
Suppose that you are on your way to a local sports store to purchase socks. On the way, you pass by either a Nordstrom (prestigious brand) or a Wal-Mart (thrifty brand). When you arrive at the sports store you see two brand options: Nike and Hanes. Do you think your selection would be influenced by the previous exposure to either the prestigious Nordstrom brand or the thrifty Wal-Mart brand?
To answer this question, Chartrand et al. (2008) conducted a study to determine if priming would affect consumer behavior.
The study included 51 participants that were asked to unscramble a set of 5 words to form a sentence of only 4 words. Half unscrambled words such as (he prestige what want did), and the other half (he frugal what want did). The two key terms were “prestige” and “frugal.”
This was followed by all participants doing 5-minutes of unrelated tasks.
Next, the participants read a hypothetical description of a scenario in which they needed to purchase a pair of crew socks. They were given the choice of either Nike socks (1 pair for $5.25) or Hanes (2 pair for $6).
The results indicated that “a greater proportion of participants chose the higher-priced Nike socks in the prestige condition than in the thrift condition” (p. 192).
Although at the end of the study all of the participants did not think their preference could have been affected by the earlier priming, it clearly was.
5. Implicit Memory and Depression
Researchers and clinicians have documented that people suffering from depression often recall previous life experiences that are negative. This is often referred to as mood-congruent-memory (MCM): the tendency for people to remember information that is consistent with their mood.
Scientists have debated whether this is a result of implicit memory bias or best explained by other theoretical frameworks (Watkins, 2002).
For example, when a depressed person attends a social gathering, it is often the case that they recall negative moments that occurred during the event. They may in fact dwell on one particular interaction, while seemingly forgetting other, more positive interactions.
As Watkins explains,
“…the tendency for depressives to dwell on more negative than positive aspects of an experience (referred to by cognitive therapists as the mental filter), could be the result of a negative implicit memory bias regarding the event….It could be that the reason they are dwelling on this event is that it more easily comes to mind through implicit retrieval” (p. 382-384).
Implicit memory happens beyond the threshold of conscious awareness. It can affect our behavior, even though we are not aware of its influence.
Implicit memory requires very little cognitive effort and minimal cognitive capacity. Perhaps the best example of this phenomenon is when playing a well-rehearsed song on the piano or other musical instrument.
It is possible to play the song with near perfection, while at the same time allowing one’s mind to drift and ponder completely unrelated subjects.
The priming of concepts in implicit memory has been shown to influence the purchasing preferences of consumers. Similarly, depressed individuals may recall negative over positive events as a result of a negative implicit memory bias.
Scientists have been studying implicit memory for over 50 years. Continued research will undoubtedly result in further advancement of our understanding of memory and human behavior.
Chartrand, T. L., Huber, J., Shiv, B., & Tanner, R. J. (2008). Nonconscious goals and consumer choice. Journal of Consumer Research, 35(2), 189-201.
Dew, I. T. Z., & Cabeza, R. (2011). The porous boundaries between explicit and implicit memory: behavioral and neural evidence. Annals of the New York Academy of Sciences, 1224(1), 174–190. https://doi.org/10.1111/j.1749-6632.2010.05946.x
Glisky, E.L. (2017). Implicit Memory. In: Kreutzer, J., DeLuca, J., Caplan, B. (Eds) Encyclopedia of Clinical Neuropsychology. Springer, Cham. https://doi.org/10.1007/978-3-319-56782-2_1129-3
Schacter, Daniel & Chiu, C-Y & Ochsner, Kevin. (1993). Implicit Memory: A Selective Review. Annual Review of Neuroscience, 16, 159-82. https://doi.org/10.1146/annurev.ne.16.030193.001111
Squire, L.R. (2004). Memory systems of the brain: A brief history and current perspective. Neurobiology of Learning and Memory, 82(3), 171–177. https://doi.org/10.1016/j.nlm.2004.06.005
Squire, L. R. (2009). The Legacy of Patient H.M. for Neuroscience. Neuron, 61, 6–9. https://doi.org/10.1016/j.neuron.2008.12.023
Squire, L. R., & Dede, A. J. O. (2015). Conscious and unconscious memory systems. Cold Spring Harbor Perspectives in Medicine, 5(1). https://doi.org/10.1101/cshperspect.a021667
Watkins, P. C. (2002). Implicit memory bias in depression. Cognition & Emotion, 16(3), 381-402.
Schacter et al. (1993) “Explicit memory entails intentional or conscious recollection of previous experiences” (p. 159).