Procedural memory
Procedural memory is a type of implicit memory (unconscious, long-term memory) which aids the performance of particular types of tasks without conscious awareness of these previous experiences.
Procedural memory guides the processes we perform, and most frequently resides below the level of conscious awareness. When needed, procedural memories are automatically retrieved and utilized for execution of the integrated procedures involved in both cognitive and motor skills, from tying shoes, to reading, to flying an airplane. Procedural memories are accessed and used without the need for conscious control or attention.
Procedural memory is created through procedural learning, or repeating a complex activity over and over again until all of the relevant neural systems work together to automatically produce the activity. Implicit procedural learning is essential for the development of any motor skill or cognitive activity.
History
The difference between procedural and
McDougall[
Working memory
Models of working memory primarily focused on declarative memory until Oberauer suggested that declarative and procedural memory may be processed differently in working memory.[3] The working memory model is thought to be divided into two subcomponents; one is responsible for declarative, while the other represents procedural memory.[4][5] These two subsections are considered to be largely independent of each other.[6] It has also been determined that the process for selection may be very similar in nature when considering either modality of working memory.[7]
Acquisition of skill
The acquisition of skill requires practice. Merely repeating a task alone, however, does not ensure the acquisition of a skill. Skill acquisition is achieved when an observed behaviour has changed due to experience or practice. This is known as learning and is not directly observable.[8] The information processing model, which incorporates this idea of experience, proposes that skills develop from the interaction of four components central to information processing.[8] These components include: processing speed, the rate at which information is processed in our processing system; breadth of declarative knowledge, the size of an individual's factual information store; breadth of procedural skill, the ability to perform the actual skill; and processing capacity, synonymous with working memory. The processing capacity is of importance to procedural memory because through the process of proceduralization an individual stores procedural memory. This improves skill usage by linking environmental cues with appropriate responses.
One model for understanding skill acquisition was proposed by Fitts (1954) and his colleagues. This model proposed the idea that learning was possible through the completion of various stages. The stages involved include:
- Cognitive phase[9][10]
- Associative phase[9][10]
- Autonomous phase (also called the procedural phase)[9][10]
Cognitive phase
At this point in Fitts' (1954) model of skill acquisition individuals come to understand what an observed skill is composed of. Attention at this point in the process is significant for the acquisition of skill. This process involves breaking down the desired skill to be learned into parts and understanding how these parts come together as a whole for the correct performance of the task. The way an individual organizes these parts is known as schemas. Schemas are important in directing the acquisition process and the way an individual comes to choose schemas is described by metacognition.[9][10]
Associative phase
The associative phase of the Fitts (1954) model involves individuals repeated practice until patterns of responding emerge. At this part in the model, actions of the skill become learned (or
Autonomous phase
This is the final phase in Fitts' (1954) model, and it involves perfecting skill acquisition. The ability to discriminate important from unimportant stimuli are made quicker and less thought process is required because the skill has become automated. Important to this phase of the model is experience and factual knowledge store for the observed skill.[9][10]
Alternative view: the "predictive cycle"
Another model for understanding skill acquisition through procedural memory has been proposed by Tadlock (2005).[11] The model is significantly different from Fitts' 1954 view in that it does not require conscious understanding of a skill's components. Rather, the learner is only required to maintain in conscious awareness a concept of the desired result. Tadlock has applied the view successfully to reading remediation (Scott et al., 2010[12]). The stages involved include:
- Attempt
- Fail
- Implicitly analyze the result
- Implicitly decide how to change the next attempt so that success is achieved
The stages are repeated over and over until the learner builds or remodels the neural network to guide an activity appropriately and accurately without conscious thought. The context for this view is similar to how physical therapy works to help brain-injured patients recover lost functions. The patient maintains the desired result (e.g., control over hand movement) while making repeated attempts, without conscious awareness of the neural activity required to make the hand move. The patient continues to make attempts until movement is achieved. In the case of brain injury, how much progress is made depends upon the extent of the injury and the "mental force" or "will power" applied by the individual. Most individuals with reading problems have brains unaffected by brain injury, but negatively affected by an undefined problem with early learning in the area of reading. Because the brain is otherwise healthy, Tadlock has used highly structured methods associated with the Predictive Cycle to successfully remediate individuals with mild to severe reading problems (including dyslexia).[citation needed]
Practice and the power law of learning
Practice can be an effective way to learn new skills if knowledge of the result, more commonly known as feedback, is involved.[13][14] There is an observed phenomenon known as the power law of learning, which predicts the rate of skill acquisition over practice time. The power law of learning says that learning occurs at the fastest rate in the beginning then drastically tapers off. The rate at which practice loses its ability to sharpen execution is independent from the skill being practiced and the type of animal learning the skill. For example, participants in a reading speed study made the greatest leap in the first days of the experiment, while additional days of practice saw only slight improvement.[15]
The power law of learning can be overcome if the subject is shown a more effective way to accomplish the task. A study subject was shown a film comparing his task performance, kicking a target as rapidly as possible, with that of a known way of minimizing kicking time. Though the subject had reached the limit of his ability to improve through practice as predicted by the power law of learning, viewing the film resulted in a breakthrough in his ability that defied the power law of learning. Viewing the film is an example of observational learning, which effectively gives the viewer new memories of a technique to draw upon for his or her future performances of the task.[16]
Tests
Pursuit rotor task
A device used to study visual-motor tracking skills and
The pursuit rotor task is a simple pure visual-motor tracking test that has consistent results within age groups.[20] This displays a measurement of procedural memory as well as demonstrates the participant's fine motor skills. The pursuit rotor task tests the fine-motor skills which are controlled by the motor cortex illustrated by the green section below.
[21] The results are then calculated by the participant's time-on and time-off the object. Amnesic participants show no impairment in this motor task when tested at later trials. It does however seem to be affected by lack of sleep and drug use.[22]
Serial reaction time task
This task involves having participants retain and learn procedural skills that assess specific memory for procedural-motor skill.
Mirror tracing task
This task looks at the integration of the senses more specifically as it is a visual motor test where the participants learn a new motor skill involving hand–eye coordination.[21] Evidence is shown for procedural memory as amnesic participants are able to learn and retain this task. Drawing the image is the work of your procedural memory; once you figure out how to draw the image in the mirror you have little difficulty the second time. Individuals with Alzheimer's disease are not able to recall the skills acquired in a mirror tracing task, but they acquire the procedural performance ability regardless.[24]
Weather prediction task
Specifically, this task uses experimental analysis of weather prediction. As a probability learning task, the participant is required to indicate what strategy they are using to solve the task. It is a cognitively-oriented task that is learned in a procedural manner.[24] It is designed using multidimensional stimuli, so participants are given a set of cards with shapes and then asked to predict the outcome. After the prediction is made participants receive feedback and make a classification based on that feedback.[25] For example, the participant can be shown one pattern and then asked to predict whether the pattern indicates good or bad weather. The actual weather outcome will be determined by a probabilistic rule based on each individual card. Amnesic participants learn this task in training but are impaired in later training control.[25]
Choice reaction task
Choice reaction tasks have been used to assess working memory.[26] It has been determined to be useful in gauging procedural working memory by asking participants to follow stimulus-reaction rules.[27]
Expertise
Divided attention
There are several factors that contribute to the exceptional performance of a skill: memory capacities,[28][29] knowledge structures,[30] problem-solving abilities,[31] and attentional abilities.[32] They all play key roles, each with its own degree of importance based on the procedures and skills required, the context, and the intended goals of the performance. Using these individualized abilities to compare how experts and novices differ regarding both cognitive and sensorimotor skills has provided a wealth of insight into what makes an expert excellent, and conversely, what sorts of mechanisms novices lack. Evidence suggests that an often overlooked condition for skill excellence is attentional mechanisms involved in the effective utilization and deployment of procedural memory during the real-time execution of skills. Research suggests that early in skill learning, execution is controlled by a set of unintegrated procedural steps that are held in working memory and attended to one-by-one in a step-by-step fashion.[33][34][35] The problem with this is that attention is a limited resource. Therefore, this step-by-step process of controlling task performance occupies attentional capacity which in turn reduces the performer's ability to focus on other aspects of the performance, such as decision making, fine motor-skills, self-monitoring of energy level and "seeing the field or ice or court". However, with practice, procedural knowledge develops, which operates largely outside of working memory, and thus allows for skills to be executed more automatically.[34][36] This, of course, has a very positive effect on overall performance by freeing the mind of the need to closely monitor and attend to the more basic, mechanical skills, so that attention can be paid to other processes.[32]
Choking under pressure
It is well established that highly practiced, over-learned skills are performed automatically; they are controlled in real time, supported by procedural memory, require little attention, and operate largely outside of working memory.[37] However, sometimes even experienced and highly skilled performers falter under conditions of stress. This phenomenon is commonly referred to as choking, and serves as a very interesting exception to the general rule that well-learned skills are robust and resistant to deterioration across a wide range of conditions.[38] Although not well understood, it is widely accepted that the underlying cause of choking is performance pressure, which has been defined as an anxious desire to perform very well in a given situation.[38] Choking is most often associated with motor skills, and the most common real-life instances are in sports. It is common for professional athletes who are highly trained to choke in the moment and perform poorly. However, choking can occur within any domain that demands a high level of performance involving complex cognitive, verbal or motor skills. "Self-focus" theories suggest that pressure increases anxiety and self-consciousness about performing correctly, which in turn causes an increase in attention paid to the processes directly involved in the execution of the skill.[38] This attention to the step-by-step procedure disrupts the well-learned, automatic (proceduralized) performance. What was once an effortless and unconscious retrieval execution of a procedural memory becomes slow and deliberate.[36][39][40][41] Evidence suggests that the more automated a skill is the more resistant it is to distractions, performance pressure, and subsequent choking. This serves as a good example of the relative durability of procedural memory over episodic memory. In addition to deliberate practice and automatization of skills, self-consciousness training has been shown to help with reducing the effect of choking under pressure.[38]
Rising to the occasion
If choking on skill-based or co-ordination oriented tasks requires the pressure of the situation to cause the performer's increased conscious attention to his or her process of performance, then the reverse can also be true. A relatively unexplored area of scientific research is the concept of "rising to the occasion." One common misconception is that a person must be an expert in order to have consistent success under pressure. On the contrary, implicit knowledge has been hypothesized to only partially mediate the relationship between expertise and performance.[42] It works closely with a perceived control of the task, and can often trump expertise if the performer embodies procedural comfort within the domain. Traditionally, "rising to the occasion" or being "clutch" has been used in reference to sporting feats of particular excellence given the magnitude of the event, however there is increasing awareness to the phenomenon in our everyday life. How one performs under circumstances that do not necessarily present immediate or grave consequence, but do require the performer to actively access a conscious mechanism to perform in unfamiliar or uncomfortable settings, is a concept that may prove educationally beneficial across a variety of disciplines and activities.[43]
Famous examples of choking
- 1996 Masters golf tournament, Greg Norman lost to Nick Faldo
- 1993 Wimbledon women's final, Jana Novotná lost to Steffi Graf
- 2011 Masters golf tournament, Rory McIlroy started the final day first, but dropped 8 shots in 3 holes at the turn.
- 2019 President's Trophy winning Tampa Bay Lightning swept by 8th seed Columbus Blue Jackets in round 1 of the NHL playoffs.
Expertise-induced amnesia
This phenomenon is based on the assumption that reducing or diverting the amount of
Genetic influence
Genetic makeup has been found to impact skill learning and performance, and therefore plays a role in achieving expertise. Using the pursuit rotor task, one study examined the effects of practice in identical and fraternal twins raised in separate homes. Because identical twins share 100% of their genes while fraternal twins share 50%, the impact of genetic makeup on skill learning could be examined. The results of the pursuit rotor task test became more identical with practice over time for the identical twins, whereas the results for the fraternal twins became more disparate with practice. In other words, the performance of the skill by the identical twins became closer to 100% identical, while the fraternal twins' skill performance became less identical, suggesting the 50% difference in genetic makeup is responsible for the difference in skill performance. The study shows that more practice leads to a closer representation of a person's innate capability, also known as talent. Therefore, some of the differences people show after extended practice increasingly reflects their genetics. The study also confirmed the idea that practice improves skill learning by showing that, in both the identical and fraternal groups, more practice aided in shedding ineffective tendencies in order to improve execution of a given skill.[45][46] Currently, the link between learning and genetics has been limited to simple task learning, while a link to more complex forms of learning, such as the learning of cognitive skills, has not been confirmed.[47]
Anatomical structures
Striatum and basal ganglia
The
The striatum is unique because it lacks the
Current understanding of brain anatomy and physiology suggests that striatal neural plasticity is what allows basal ganglia circuits to communicate between structures and to functionally operate in procedural memory processing.[53]
Cerebellum
The
Limbic system
The limbic system is a group of unique brain areas that work together in many interrelated processes involved in emotion, motivation, learning and memory. Current thinking indicates that the limbic system shares anatomy with a component of the neostriatum already credited with the major task of controlling procedural memory. Once thought to be functionally separate, this vital section of the brain found on the striatum's back border has only recently been linked to memory and is now being called the marginal division zone (MrD).[56] A special membrane protein associated with the limbic system is said to concentrate in related structures and to travel towards the basal nuclei. To put things simply, the activation of brain regions that work together during procedural memory can be followed because of this limbic system associated membrane protein and its application in molecular and immunohistochemistry research.[57]
Physiology
Dopamine
Dopamine is one of the more known neuromodulators involved in procedural memory. Evidence suggests that it may influence neural plasticity in memory systems by adapting brain processing when the environment is changing and an individual is then forced to make a behavioural choice or series of rapid decisions. It is very important in the process of "adaptive navigation", which serves to help different brain areas respond together during a new situation that has many unknown stimuli and features.[58] Dopamine pathways are dispersed all over the brain and this allows for parallel processing in many structures all at the same time. Currently most research points to the mesocorticolimbic dopamine pathway as the system most related to reward learning and psychological conditioning.[59]
At the synapse
Recent findings could help explain the relationship between procedural memory, learning and synaptic plasticity at the level of the molecule. One study used small animals lacking normal levels of CREB family transcription factors to look at the processing of information in the striatum during various tasks. Although poorly understood, results show that CREB function is needed at the synapse for linking the acquisition and storage of procedural memory.[60]
Disorders
Disorders have been important for the understanding of memory systems. The memory abilities and inhibitions of patients with various diseases played a major role in establishing the distinction that long-term memory consists of different types of memory, more specifically declarative memory and procedural memory. Furthermore, they have been important for illuminating the structures of the brain that comprise the neural network of procedural memory.
Alzheimer's disease and dementia
Current Research indicates that procedural memory problems in
Tourette syndrome
This disease of the central nervous system, like many other procedural-memory related disorders, involves changes in the associated subcortical brain area known as the striatum. This area and the brain circuits closely interacting with it from the basal ganglia are affected both structurally and at a more functional level in the people affected by
One study has found that those with Tourette syndrome have enhanced procedural learning. Subjects with Tourette's syndrome were found to have more quickly processed procedural knowledge and more accurately learned procedural skills than their typically developed counterparts. Another study found that subjects with Tourette's syndrome displayed faster processing of rule-based grammar than typically developed subjects. Two possible explanations exist for these results. One explanation is that once a person with Tourette's syndrome has learned a procedure, there is a mechanism that supports more accelerated processing. Second, because procedural memory subserves sequencing, and grammar recruits sequencing, an enhancement of grammatical processing was seen in those with Tourette's syndrome due to their improved procedural memories.[63]
Human immunodeficiency virus (HIV)
Neural systems used by procedural memory are commonly targeted by
Huntington's disease
Despite Huntington's disease being a disorder that directly affects striatal areas of the brain used in procedural memory, most individuals with the condistion display different memory problems from people with striatum related brain diseases.[67] In more advanced stages of the disease, however, procedural memory is affected by damage to the important brain pathways that help the inner subcortical and prefrontal cortex parts of the brain to communicate.[68]
Obsessive compulsive disorder
Neuroimaging studies show that
Parkinson's disease
Parkinson's disease is known to affect selective areas in the frontal lobe area of the brain. Current scientific information suggests that the memory performance problems notably shown in patients are controlled by unusual frontostriatal circuits.[70] Parkinson's patients often have difficulty with the sequence-specific knowledge that is needed in the acquisition step of procedural memory.[71] Further evidence suggests that the frontal lobe networks relate to executive function and only act when specific tasks are presented to the patient. This tells us that the frontostriatal circuits are independent but able to work collaboratively with other areas of the brain to help with various things such as paying attention or focusing.[72]
Schizophrenia
MRI studies have shown that
Drugs
Overall, research concerning the effects of drugs on procedural memory is still limited. This limitation stems from the fact that procedural memory is implicit and thus more difficult to test, as opposed to declarative memory which is more pronounced and thus easier memory system to use for determining the effects of an observed drug.
Alcohol
While the effects of alcohol have been studied immensely, even with respect to memory, there is limited research examining the effects of alcohol on procedural memory. Research conducted by Pitel A. L. et al. suggests that alcoholism impairs the ability to acquire semantic concepts. In this study, while semantic concepts were understood, procedural memory was often not automated. A potential reason for this finding is that poor learning strategies are used by alcoholics compared to non-alcoholics.[76]
Cocaine
It is evident that long-term
Psychostimulants
Most
Sleep
Practice is clearly an important process for learning and perfecting a new skill. With over 40 years of research, it is well established in both humans and animals that the formation of all forms of memory are greatly enhanced during the brain-state of sleep. Furthermore, with humans, sleep has been consistently shown to aid in the development of procedural knowledge by the ongoing process of memory consolidation, especially when sleep soon follows the initial phase of memory acquisition.
Whether a skill is learned explicitly (with attention) or implicitly, each plays a role in the offline consolidation effect. Research suggests that explicit awareness and understanding of the skill being learned during the acquisition process greatly improves the consolidation of procedural memories during sleep.[99] This finding is not surprising, as it is widely accepted that intention and awareness at time of learning enhances the acquisition of most forms of memory.
Language
Language works because of the brain's ability to retrieve pieces of information from memory and then combine those pieces into a larger, more complex unit based on context. The latter part of this process is called unification.[100] Results of several studies provide evidence that suggests procedural memory is not only responsible for sequential unification, but for syntactic priming and grammatical processing as well.
One study used patients with
Another study's results support the hypothesis that procedural memory subserves grammar. The study involved a series of tests for two groups: one typically developing (TD) group and one group with developmental language disorder (DLD). Those with DLD have difficulty with proper grammar usage, due to deficits in procedural memory function. Overall, the TD group performed better on each task and displayed better speed in grammatical processing than the DLD group. Therefore, this study shows that grammatical processing is a function of procedural memory.[102]
According to a study carried out in 2010 by Dalhousie University researchers, spoken languages which require the use of helping words or suffixes, rather than word order, to explain subject-object relationships rely on procedural memory. Word-order dependent languages rely on short-term memory for equivalent tasks.[103]
See also
- Automaticity – Ability to do things without occupying the mind with the low-level details required
- Dreyfus model of skill acquisition – Model of learning
- Explicit memory – Type of long-term human memory
- Kata – Detailed choreographed patterns of movements in martial arts
- Motor learning – Organism's movements that reflect changes in the structure / function of the nervous system
- Muscle memory – Consolidating a motor task into memory through repetition
- Neuroplasticity – Ability of the brain to continuously change
- Procedural knowledge – Ability to do something
- Sleep and memory – Relationship between sleep and memory
- Working memory – Cognitive system for temporarily holding information
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