Simply Psychology Logo

Procedural Memory

By Ayesh Perera, published January 26, 2021

Take-home Messages
  • Procedural memory is a category of long-term memory that involves recollections to which a person has no direct conscious awareness. It can only be demonstrated indirectly through some type of motor action, for example, how to swim or ride a bicycle
  • Procedural memory is a part of the implicit long-term memory responsible for knowing how to do things.
  • Professor Brenda Milner’s experiments with the amnesic patient Henry Molaison (HM) played a vital role in the initial scientific investigation into procedural memory.
  • HM was able to form some types of LTM after his surgery but not others. He was able to learn a new motor skill ‘mirror drawing’ but he could not remember learning it. This suggests a distinction can be made between procedural and explicit memories.
  • The operation of procedural memory involves the functions of the dorsolateral striatum, the cerebellum, and the limbic system.
  • Studies show that REM (Rapid Eye Movement) sleep following SWS (Slow-Wave Sleep), immediately after the acquisition of a new skill significantly enhances procedural memory consolidation.

Procedural memory is a type of long-term implicit memory that involves the performance of certain cognitive and motor tasks without the conscious retrieval of past information (Lum, Conti-Ramsden, Page & Ullman, 2011). It is the memory for skilled actions, such as how to brush your teeth, how to drive a car, how to swim the crawl (freestyle) stroke.

Procedural memories are inadvertently retrieved and unconsciously used for the performance of various motor skills and cognitive tasks.

Examples of Procedural Memory

Actions involving procedural memory often include tasks learned early in childhood, which have become ingrained over time through repetition. The following tasks employ procedural memory:


    Tying shoes

    Riding a bicycle



History and Background

Serious psychological and philosophical discussion on the topic of memory has existed for nearly two centuries. The American psychologist and philosopher William James (1890) was among the early figures to point out the possible difference between habit and memory.

Despite much investigation to memory, however, Brenda Milner of McGill University is generally credited with producing the first convincing evidence in 1962, indicating a division between declarative memory and procedural memory (Squire, 2004).

This was demonstrated via her experiments with the amnesic patient H.M. (Henry Molaison). H.M. had had a bilateral medial temporal lobectomy to cure his epilepsy (Squire, 2009). The partially successful surgery had left him unable to form new memories.

Nonetheless, H.M. was able to learn mirror drawing which involved hand-eye coordination. H.M.’s experience indicated that a single system did not constitute the entirety of memory.

Subsequent research conducted on amnesic patients revealed that this ability to learn and perform certain activities extended beyond motor skills (such as mirror drawing), and included cognitive tasks as well. Some had suggested that amnesia might merely be a retrieval deficit.

However, it was later confirmed that amnesia involved an actual memory deficit (rather than a mere retrieval deficit), but that it still left unharmed a domain for memory which is used for skill development.

Procedural Memory vs. Declarative Memory

Cohen and Squire (1980) drew a distinction between declarative knowledge and procedural knowledge.

Procedural knowledge involves “knowing how” to do things. It included skills, such as “knowing how” to playing the piano, ride a bike; tie your shoes and other motor skills.

Procedural memory is a type of long-term implicit memory which is formed unconsciously and retrieved effortlessly.  For example, we brush our teeth with little or no awareness of the skills involved.

Declarative knowledge involves “knowing that”, for example London is the capital of England, zebras are animals, your mum's birthday etc.  There are two types: semantic memory and episodic memory.

Declarative memory (also known as explicit memory) is a type of long-term memory which involves the intentional and conscious recollection of previous personal experiences and learned information (Hine & Tsushima, 2018).

Recalling information from declarative memory involves some degree of conscious effort – information is consciously brought to mind and “declared”.

It is also important to note that procedural memories are relatively harder to explain (Cherry, 2020). For instance, it is difficult to fully explain in words how to drive a car. Nonetheless, communicating the details of how to fix a car engine in a classroom (by retrieving one’s declarative memory) is relatively easier.

Evidence for the distinction between declarative and procedural memory has come from research on patients with amnesia. Typically, amnesic patients have great difficulty in retaining episodic and semantic information following the onset of amnesia.

Their memory for events and knowledge acquired before the onset of the condition tends to remain intact, but they can’t store new episodic or semantic memories. In other words, it appears that their ability to retain declarative information is impaired.

However, their procedural memory appears to be largely unaffected. They can recall skills they have already learned (e.g. riding a bike) and acquire new skills (e.g. learning to drive).

Improving Procedural Memory

Research indicates that sleep aids the development of procedural knowledge via ongoing memory consolidation which passes new memories from a fragile condition to a robust and stable state (Walker, Brakefield, Morgan, Hobson & Stickgold, 2002). This is especially true when the initial phase of memory acquisition is immediately followed by sleep.

Even though the consolidation of procedural memories was long considered to be solely a function of time, recent studies indicate that for some types of learning, sleep alone enhances memory consolidation (Brashers-Krug, Shadmehr &, 1996) (Fischer, Hallschmid, Elsner & Born, 2002).

Brief naps involving non-rapid eye movement, however, does not seem to improve procedural memory (Siegel, 2001).

Procedural memory is best enhanced by REM (Rapid Eye Movement) sleep following SWS (Slow-Wave Sleep), which comprises stage three and four, as well as the deepest type of NREM sleep (Karni, Meyer, Rey-Hipolito, Jezzard, Adams, Turner & Ungerleider, 1998).

This mode of sleep can be exceedingly beneficial if it immediately ensues the acquisition of a new skill. This is because a full night or day of sleep after learning a new skill can significantly enhance memory consolidation (Mednick et al, 2003).

However, research also points out that these potential gains would be prevented if REM sleep is interrupted (Karni, Meyer, Rey-Hipolito, Jezzard, Adams, Turner & Ungerleider, 1998).

Brain Regions Related to Procedural Memory

The chief neuronal cell nucleus related to procedural memory is the dorsolateral striatum which aids the acquisition of new habits (Alexander & Crutcher, 1990). Additionally, evidence suggests that striatal neural plasticity permits the basal ganglia circuits to help process procedural memory as well as communicate between structures (Kreitzer, 2009).

Moreover, the cerebellum plays a vital role in rectifying the movement and adjusting the motor agility of procedural activities such as playing sports, playing instruments, and painting (Saywell & Taylor, 2008).

The cerebellum also helps automate the unconscious process involving procedural skill learning. Recent evidence implies that the cerebellar cortex holds the engram—which is considered to be the location wherein memory dwells (Nagao & Kitazawa, 2008).

Moreover, the neostriatum which controls procedural memory shares anatomy with the limbic system (Shu, Bao, Li, Chan & Yew, 2000). Although previously considered to be a functionally separate entity, recent evidence indicates that the MrD (marginal division zone) is linked to memory.

Additionally, dopamine, a neuromodulator related to procedural memory, seems to adapt brain processing to new environments which demand behavior modification, thereby impacting neural plasticity within memory systems (Mizumori, Puryear & Martig, 2009).

Furthermore, the examination of synaptic plasticity at the molecular level demonstrates that CREB function maybe connecting the acquisition and the storage of procedural memory (Pittenger, Fasano, Mazzocchi-Jones, Dunnett, Kandel & Brambilla, 2006).

About the Author

Ayesh Perera recently graduated from Harvard University, where he studied politics, ethics and religion. He is presently conducting research in neuroscience and peak performance as an intern for the Cambridge Center for Behavioral Studies, while also working on a book of his own on constitutional law and legal interpretation.

How to reference this article:

Prera, A (2021, Jan 26). Procedural memory. Simply Psychology.

APA Style References

Alexander, G. E., & Crutcher, M. D. (1990). Functional architecture of basal ganglia circuits: neural substrates of parallel processing. Trends in neurosciences, 13(7), 266-271.

Brashers-Krug, T., Shadmehr, R., & Bizzi, E. (1996). Consolidation in human motor memory. Nature, 382(6588), 252-255./p>

Cohen, N. J., & Squire, L. R. (1980). Preserved learning and retention of pattern analyzing skill in amnesia: Dissociation of knowing how and knowing that. Science, 210, 207–209.

Fischer, S., Hallschmid, M., Elsner, A. L., & Born, J. (2002). Sleep forms memory for finger skills. Proceedings of the National Academy of Sciences, 99(18), 11987-11991.

Hine, K., & Tsushima, Y. (2018). Not explicit but implicit memory is influenced by individual perception style. Plos one, 13(1), e0191654.

James, W. (1890). The principles of psychology. New York. Holt and company.

Karni, A., Meyer, G., Rey-Hipolito, C., Jezzard, P., Adams, M. M., Turner, R., & Ungerleider, L. G. (1998). The acquisition of skilled motor performance: fast and slow experience-driven changes in primary motor cortex. Proceedings of the National Academy of Sciences, 95(3), 861-868.

Kreitzer, A. C. (2009). Physiology and pharmacology of striatal neurons. Annual review of neuroscience, 32, 127-147.

Lum, J. A., Conti-Ramsden, G., Page, D., & Ullman, M. T. (2012). Working, declarative and procedural memory in specific language impairment. Cortex, 48(9), 1138-1154.

Mednick, S., Nakayama, K., & Stickgold, R. (2003). Sleep-dependent learning: a nap is as good as a night. Nature neuroscience, 6(7), 697-698.

Milner, B. (1962). Les troubles de la memoire accompagnant des lesions hippocampiques bilaterales. Physiologie de l’hippocampe, 107, 257-272.

Milner, B. (1998). The History of Neuroscience in Autobiography, Volume 2, L.R. Squire, ed. (San Diego: Academic Press), pp. 276–305.

Milner, B., Corkin, S., & Teuber, H. L. (1968). Further analysis of the hippocampal amnesic syndrome: 14-year follow-up study of HM. Neuropsychologia, 6(3), 215-234.

Nagao, S., & Kitazawa, H. (2008). Role of the cerebellum in the acquisition and consolidation of motor memory. Brain and nerve= Shinkei kenkyu no shinpo, 60(7), 783-790.

Pittenger, C., Fasano, S., Mazzocchi-Jones, D., Dunnett, S. B., Kandel, E. R., & Brambilla, R. (2006). Impaired bidirectional synaptic plasticity and procedural memory formation in striatum-specific cAMP response element-binding protein-deficient mice. Journal of Neuroscience, 26(10), 2808-2813.

Saywell, N., & Taylor, D. (2008). The role of the cerebellum in procedural learning—Are there implications for physiotherapists’ clinical practice?. Physiotherapy theory and practice, 24(5), 321-328.

Shu, S. Y., Bao, X. M., Zhang, C., Li, S. X., Chan, W. Y., & Yew, D. (2000). A new subdivision, marginal division, in the neostriatum of the monkey brain. Neurochemical Research, 25(2), 231-237.

Siegel, J. M. (2001). The REM sleep-memory consolidation hypothesis. Science, 294(5544), 1058-1063.

Squire, L. R. (2004). Memory systems of the brain: a brief history and current perspective. Neurobiology of Learning and Memory, 82(3), 171-177.

Squire, L. R. (2009). The legacy of patient HM for neuroscience. Neuron, 61(1), 6-9.

Walker, M. P., Brakefield, T., Morgan, A., Hobson, J. A., & Stickgold, R. (2002). Practice with sleep makes perfect: sleep-dependent motor skill learning. Neuron, 35(1), 205-211.

How to reference this article:

Prera, A (2021, Jan 26). Procedural memory. Simply Psychology.

Print Friendly and PDF

Home | About | A-Z Index | Privacy Policy | Contact Us

This workis licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 Unported License.

Company Registration no: 10521846