On a daily basis, you complete actions without consciously reminding yourself how to do them. Just in your morning routine, there are a number of procedural tasks that involve the use of your motor skills without conscious awareness: you get up and make your bed, walk to your bathroom and hop in the shower, make coffee, cook an omelet (without looking at a recipe), get dressed and tie your shoes, and then ride your bike to work. Now imagine trying to describe to someone how to do these things step by step, or trying to explain when and how you learned them. They’re simple, easy actions that you barely have to think about, that in many cases, would be difficult to put into words. 

The reason that you’re able to complete all these actions is thanks to your procedural memory, a type of implicit memory used to perform actions that require motor skills. You start to form procedural memories early in life, when you learn how to walk, talk, and interact with your environment. As you practice the actions, synaptic connections in your brain are strengthened, which means the memory becomes deeply ingrained, allowing you to repeat the skill automatically and unconsciously. You don’t need to think about how to walk before doing it—your brain just knows how and signals your body accordingly.¹

Procedural memory is crucial for our day-to-day life as it guides so much of what we do. Being able to complete small actions without conscious thought allows our brain to focus on other, more complex tasks. Imagine if every time you sat down at your computer, you had to remind yourself how to type? You’d never get any work done! 

Motor Skills: Physical movements that we make to perform actions and interact with our environment.

Encoding: The process of transforming new sensory information into a format suitable for longer-term storage and retrieval. For procedural memory, the information moves between memory systems through repetition and practice.

Retrieval: The process of accessing information in our long-term memory. For procedural memory, retrieval is automatic and unconscious.

Long-Term Memory: A storage system in our brain where information is held for extended periods, anywhere from 30 seconds to decades. Our long-term memory has relatively unlimited capacity, allowing us to acquire new information throughout our lives without losing preexisting knowledge, however, we often make mistakes when recalling the information. Long-term memory can be subcategorized as implicit and explicit memory. 

Implicit Memory: An umbrella term for all information that is encoded and retrieved unconsciously in our long-term memory. This includes procedural memory, which is related to memories used for skills and actions. Other subtypes include classical conditioning, where associations between stimuli are learned unconsciously, and priming, where exposure to one stimulus influences a subsequent response without conscious awareness.

Explicit Memory: A type of long-term memory involving information that requires purposeful and conscious effort to recall. It contrasts with implicit memory, as you often intentionally encode and retrieve the information from your long-term storage. 

In 1890, American philosopher and psychologist William James published The Principles of Psychology. In the first volume, James explored the mind, touching on topics such as the nature of thought and consciousness and the structure of the brain. He emphasized the importance of memory for learning and described the process of encoding, storing, and retrieving information. He further distinguished between primary and secondary memory, which align closely with what we now know as short-term and long-term memory.³ 

In The Principles of Psychology, James also made a distinction between different types of information stored in our memory: habits and facts. He noted that habits are learned over time, through repetition, but once known, they become instinctive and can be recalled with little to no thought.⁴ This laid the foundation for our understanding that procedural memory is recalled in a different manner from explicit memory.

In 1949, Canadian psychologist Donald Hebb proposed the theory that “neurons that fire together, wire together.” This catchy aphorism is a concise way of saying that when an action is performed, synaptic connections between simultaneously activated neurons are reinforced, and the more the action is repeated, the stronger the neural pathway becomes. At first, it may be difficult for a child to walk, but after they have practiced the movement hundreds of times, motor skills become second nature. This theory became known as the Hebbian theory and provided insight into how actions become automatic and unconscious.⁵

In 1953, the peculiar case of Henry Gustav Molaison helped researchers to understand which parts of our brain are involved in procedural memory. Molaison had been in a bicycle accident at age seven, which over time, led to increasingly frequent and treatment-resistant epileptic fits. This prevented him from holding a steady job or leading a normal life, pushing him to undergo brain surgery in hopes of preventing future seizures. During the surgery, Molaison’s hippocampus was removed. Unfortunately, as doctors were unaware of the role of the hippocampus at this time, the surgery resulted in Molaison developing both retrograde (inability to remember past memories) and anterograde amnesia (inability to form new long-term memories).⁶

However, as researchers conducted memory tests with Molaison, they realized that not all of his memory had been impaired. Molaison was able to learn new motor skills even though he would forget events almost immediately after they occurred. Molaison was shown a five-pointed star and asked to trace its outline in pencil while he could only see his hand and the star in a mirror. Over the course of three days, Molaison improved this motor skill, even though he didn’t remember having previously completed the task. His case study provided further evidence of the distinction between explicit and implicit memory and suggested that procedural memory, a subtype of implicit memory, does not require the hippocampus.⁶ 

In the 1980s, American neuroscientist Larry Squire and his colleagues conducted extensive research into memory in both animal and human studies, which led to the discovery that the basal ganglia and cerebellum were parts of our brain involved in procedural memory. In later years, fMRI and PET scans confirmed that brain activity in these areas was present when people performed tasks involving procedural memory, like typing a sequence on a keyboard.⁵

Today, procedural memory is recognized not only as essential for physical tasks like riding a bike or playing an instrument but also as a key player in cognitive skills such as language acquisition, social routines, and even decision-making.

William James

An American philosopher and psychologist who was a leader in pragmatism, a philosophical approach that emphasizes that the consequence of actions determines their merit. Later in life, James took an interest in psychology and published The Principles of Psychology, which outlined everything research had yet discovered about the mind. In the book, James made a distinction between learning facts and habits, emphasizing how repetition builds habits that allow us to repeat tasks without conscious awareness, whereas facts have to be consciously recalled.⁷

Donald Hebb

A highly influential Canadian psychologist, often referred to as the “father of neuropsychology,” who sought to explain psychological phenomena through neuroscience. He is best known for developing the Hebbian theory, which explained that neural pathways are developed through repetition, which makes them stronger and faster and allows us to use procedural memory to perform tasks automatically and unconsciously.⁸

Henry Gustav Molaison

A patient who suffered from retrograde and anterograde amnesia after undergoing brain surgery in an attempt to prevent epileptic seizures. During the surgery, parts of his hippocampus were removed, leaving him unable to remember events from the years prior to the surgery or form new long-term memories. However, Molaison retained the ability to develop motor skills, providing evidence that procedural memory is distinct from explicit memory and relies on a different brain system.⁶ 

Larry Squire

An American neuroscientist who has focused his research on the organization and structure of memory in both humans and animals. With his team, he studied the brain structure and capabilities of neurological patients who demonstrated impaired memory, allowing him to identify that the basal ganglia and cerebellum are involved in procedural memory. Squire is currently a Professor of Psychiatry, Neurosciences, and Psychology at the University of California, San Diego.⁹ 

Procedural memory plays a foundational role in how we learn, adapt, and recover from cognitive challenges. Its influence spans disciplines, from rehabilitation and education to neuroscience and animal research, shaping how we understand skill acquisition and long-term learning.

Transforming neurorehabilitation

During a stroke, a blood clot prevents blood from circulating to your brain, which sometimes results in long-term damage. Patients who have experienced a stroke often struggle to recall past events or retain new information, but many demonstrate a continued ability to use procedural memory.

By understanding procedural memory through the development of strong neural pathways, which are strengthened over time through practice, neurorehabilitation can focus on teaching patients repetitive, task-specific training. Previously, rehabilitation for stroke patients had focused on explicit memory, but as procedural memory is better preserved, it is now recommended to leverage this type of learning. The Modified Approach to Stroke Rehabilitation (MAStR) suggests that staff simplify instructions to only three words verbally and focus on nonverbal instruction instead, such as helping a patient to move their hand, and emphasizes the importance of using the same approach every time they move the patient. The repetitive nature of MAStR helps patients regain their motor skills more quickly while in recovery.¹⁰ 

Improving learning for children

Procedural memory develops earlier than explicit memory, allowing children to learn motor skills, like walking or putting on their clothes, and cognitive routines, such as speaking using basic language structures, more easily than memorizing information consciously. 

One study conducted in 2020 showed that procedural memory develops in infants as young as nine months old. The researchers compared how 9-month-old infants performed in a Serial Reaction Time task compared to adults to determine whether infants exhibit procedural memory capabilities. In the study, participants were seated in front of three screens, where images would be shown. Sometimes, the order in which the images were shown was fixed (e.g., moving from screen A, to screen B, to screen C, and back to screen A), while other times, the order in which screens images appeared on was random. 

The researchers tracked eye movements to see how long it took participants to shift their gaze to the new image location. For both adults and infants, the researchers found that when the pattern was anticipated (the fixed sequence of screens), participants’ eyes moved more quickly to the next image, because they were unconsciously learning the sequence, allowing them to predict on which screen it would appear next.¹¹ 

The study provided evidence that implicit memory develops at a very young age, while multiple other studies have shown how explicit memory improves as people get older. Understanding this distinction is crucial for educational strategies, as it highlights the importance of incorporating repetitive, experience-based learning to leverage children's strong implicit memory capabilities.

Procedural memory in animals

Procedural memory is not unique to humans—many animals are also able to learn motor skills unconsciously. Animals demonstrate brain activity in similar brain areas, namely the basal ganglia, when conducting procedural memory tasks, suggesting that this type of implicit memory works in a similar fashion in animals as it does in humans.

Researchers in Tokyo conducted a study to see how procedural learning occurs in monkeys. Monkeys were trained to be able to press buttons in a specific order. They were shown a panel with 16 light-emitting buttons, and after they pressed a “home key,” saw two lights illuminate, prompting them to repeat the pattern. If the monkey pressed the right buttons in the correct order, they would move on to another sequence. If they pushed the wrong buttons, they had to start over. Over time, the monkeys’ performance improved, suggesting they had learned how to carry out the task unconsciously without knowing the instructions. The researchers also monitored the animals’ brain activity while completing the task and found that the basal ganglia were activated, suggesting they rely on a brain system similar to that of humans to carry out procedural tasks.¹² 

Despite its central role in learning and skill development, procedural memory is far from a settled concept. Researchers continue to debate its unconscious nature, neural underpinnings, and developmental trajectory—raising fundamental questions about how this memory system truly works.

Is procedural memory truly unconscious?

Procedural memory is characterized by its automatic and unconscious nature. However, for most procedural tasks, there was a point in time when the information or skill was consciously learned, at least in part. When we learned to talk, our parents repeated easy words like “Mama” or “food” to us, prompting us to copy them. One of your parents also likely taught you how to ride a bike, or a coach taught you how to hit a baseball. This suggests that, at the very least, encoding is not purely unconscious.

Even when discussing the retrieval of procedural memory, it is difficult to say with certainty that it is purely unconscious. It is challenging to isolate procedural memory in research studies, with some form of explicit memory often interfering. For example, in a 2021 study evaluating procedural memory, participants were shown combinations of cards with random symbols and asked to predict the weather. Some participants were given clear, explicit instructions, relying on explicit memory, while others had to learn through trial and error, leveraging procedural memory. Additionally, while performing the weather prediction task, participants were asked to complete a secondary task, such as counting. Interestingly, the two groups performed similarly— raising questions about whether procedural memory is truly unconscious, or if it can be influenced by explicit learning. This also highlights how difficult it is to isolate procedural memory in experimental settings.¹³ 

Which brain region is procedural memory dependent on?

Historically, research has focused on the role of the basal ganglia and cerebellum in procedural memory. However, more recent studies suggest there are other areas of the brain, like the prefrontal cortex, that are active when we use our motor skills, suggesting procedural memory may depend on a network of interconnected brain regions.

Other studies even show that there are other areas of our body that can impact the performance of our procedural memory. In a 2015 study, researchers tested the procedural memory of patients who had experienced injury to nerves in their right brachial plexus (an area between the neck and shoulder). fMRIs revealed that their primary motor cortex, a key player in executing motor skills, showed reduced functional connectivity across the area that controlled their right arm. The patients showed no difference in brain density compared to a control group, confirming that there was no brain damage. The researchers believe that the nerve damage caused there to be fewer synaptic connections between the right arm and the brain, resulting in diminished procedural memory and motor skills. The study suggests that procedural memory is dependent on more than just our brain, and certainly more than our basal ganglia and cerebellum.¹⁴ 

When do we develop procedural memory?

Traditionally, implicit memory has been believed to be relatively uniform and independent of things like age. Studies have shown that infants as young as nine months old demonstrate an ability to perform some tasks related to procedural memory, such as visual sequence learning. However, it takes time and practice for us to learn other procedural tasks, like riding a bike or learning grammar rules, and studies show that our basal ganglia and cerebellum continue to develop in adolescence. 

In a 2004 study, researchers compared the brain activity of children aged eight to ten and adults as they performed a serial reaction time task. Both children and adults showed that they unconsciously learned the sequence using procedural memory, but adults learned it faster. fMRI scans also showed that the basal ganglia were more activated in adults than in children, while children showed activation in more brain areas. The researchers concluded that, as the basal ganglia are still developing in children, they require additional brain regions to use procedural memory.¹⁵

Retention of procedural memory in amnesic patients

The discovery of multiple amnesic patients retaining an ability to learn procedural skills provided some of the most concrete evidence of the divide between explicit and implicit memory. In 2004, researchers from the University of Iowa Carver College of Medicine wanted to explore which types of procedural skills amnesic patients can learn, whether these skills are useful in real-life settings rather than just in lab tests, and whether there are common traits between the types of skills retained.

Researchers tested the performance of procedural memory in amnesic patients through five activities related to real-world skills:

• A weaving task where participants used a loom to weave pieces of fabric together
• A tracing task where participants had to trace geometric figures with a stylus on a screen monitor
• A control stick task where participants had to track a sequence of visual targets using a joystick
• A pouring task where participants had to pour water into a series of graduated cylinders
• A spatial sequence task where participants had to push five buttons without visual guidance

Ten patients with severe amnesia participated in the study, and their performance was compared with 25 individuals who had no brain damage or amnesia. Participants were asked to complete the task three times: once as soon as they learned the task, once twenty-four hours later, and once three months later. The learning slopes and retention of procedural memory in amnesic patients were similar to the comparison group, suggesting that complex perceptual-motor skills are well retained even when other forms of memory are lost.¹⁶

Eugene Pauly: Building habits versus remembering

One of the amnesic patients studied by American neuroscientist Larry Squire was Eugene Pauly. Squire met Pauly in 1994, when he was 72 years old and showed severe memory loss, unable to remember around forty years of his life, and incapable of learning new facts. At the age of 70, Pauly suffered from viral encephalitis, inflammation of the brain caused by a virus. Parts of his temporal lobes and hippocampus were damaged, but his basal ganglia remained intact. Squire spent sixteen years with Pauly and his family to learn more about his memory. 

In the first 12 weeks of knowing Pauly, Squire conducted dozens of tests. Pauly was unable to remember past events or form new explicit memories, failing to even remember that he had already met Squire or his team. However, Squire said that Pauly “eventually regarded us as friends and invited us into the house and went right over to the testing table.” Although Squire did not consciously remember the research team, it seemed he was able to form a habit unconsciously. Pauly was also able to learn the way around his own house and stick to a routine. This was also demonstrated by Pauly’s improved performance in motor and perceptual skills over time, shown in tasks like copying visual figures, even though Pauly denied having ever seen the figures before.¹⁷ 

In one test, Pauly had to choose the correct object from pairs. Initially, he couldn’t remember which objects were correct, but over time and repeated trials, his performance improved. Squire was curious whether Pauly was truly learning and remembering the objects, so he gave him all the cards and asked him to put the correct objects in a pile. Pauly was unable to do so, as he could only select the correct object from consistent pairings, suggesting that he wasn’t consciously learning but simply forming the habit of selecting the right object over time. This showed that Pauly was only using procedural memory, which made it difficult for him to adapt to any changes in tasks.¹⁸

Pauly’s case showed the importance of the hippocampus in forming explicit memories, whereas procedural memory is connected to the basal ganglia. His case study also provided strong evidence that procedural memories are learned unconsciously. 

Automatic Thinking

Automatic thinking is the unconscious, effortless cognitive process that we leverage for procedural thinking, as well as quick problem-solving. It is differentiated from controlled thinking, a slow mental process that we use for explicit memory encoding and recall. In this article, our writer, Triumph Kerins, explores the four quadrants that characterize automatic thinking: unawareness, unintentional, cognitively efficient, and difficult to control, and how automatic thinking causes us to be vulnerable to many cognitive biases. 

Classical Conditioning

If you’re interested in learning more about another subtype of implicit memory, classical conditioning, check out this article by our writer, Kira Warje. Classical conditioning is an unconscious learning process in which a neutral stimulus is paired with a stimulus that prompts a natural response, causing us to associate the two stimuli and leading to an automatic, conditioned response to the neutral stimulus. For example, smelling coffee may cause you to feel more awake because you begin to associate it with the effects of drinking caffeine. 

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