Learning and Memory Lecture 8 PDF

SKILL MEMORY PSYC 3022 Learning and Memory Instructor: Mala Ramesar  W H AT I S S K I L L M E M O RY Skill Memory Memory for Events A skill is an abi...

SKILL MEMORY PSYC 3022 Learning and Memory Instructor: Mala Ramesar  W H AT I S S K I L L M E M O RY Skill Memory Memory for Events A skill is an ability you can and Facts improve over time Is difficult to convey Can be communicated Skill memory consists of what to others flexibly a person knows to do and is similar to episodic and May be acquired Has content that is semantic memories without awareness consciously accessible How long after learning skills Requires several Can be acquired in a you can retrieve the skill repetitions single exposure depends on how well you have learned the skills, how often you have recalled them and how complex they are PERCEPTUAL MO TOR SKILLS Perceptual motor skills are learned movement patterns guided by sensory inputs There are two types of perceptual motor skills: Closed skills: performing predefined movements like ballet dancing, swimming Open skills: responses are based on predictions about changes in the environment like team sports Learning open and closed skills are not restricted to only humans, animals are capable of learning these skills, e.g., a dog catching a frisbee  COGNITIVE SKILLS Cognitive skills require the use of the brain to solve problems or apply strategies Research into cognitive skills utilises procedures that participants can acquire quickly, such as those required to solve puzzles like the tower of Hanoi This puzzle requires persons to move disks from 1 of 3 poles on the condition that only 1 disk can be moved at a time and a larger disk cannot be placed on top of a smaller disk The ability to solve this puzzle overtime indicates that persons are developing new problem solving strategies  COGNITIVE SKILLS Cognitive skills are not unique to humans Researchers and animal trainers have demonstrated that animals can use tools Researchers observed chimpanzees in the wild using stones to crack open a nut Using tools require both perceptual motor skill and cognitive skill The physical use of a tool is a perceptual motor skill while recognising that an object can be used as a tool is a cognitive skill  We are born with different skills and improvement of those skills rests on the extent to which we practice People who seem to master a skill or talent are considered to have a gift EXPERTISE People who perform better than most are AND TALENT considered an expert What role does talent play in achieving expertise? Psychologists have attempted to answer this using twin studies [identical and fraternal] reared separately  Participants were trained in the rotary pursuit task which requires perceptual motor skill learning Over time, participants were able to adjust both speed and trajectory of their arm movements This research found identical twins abilities on this task improved similarly as training EXPERTISE progressed, whereas fraternal twins became more dissimilar AND TALENT That is the performance of identical twins correlated strongly over time on performance of the rotary pursuit task This can be interpreted as practice decreases the effects of participants’ prior experiences on accuracy but instead, increases the effects of their genetic influences  Practice is simple, it is based on the concept that the more you perform a skill, the better and faster you would be able to perform it Edward Thorndike blindfolded participants and asked them to draw a line 3 inches long Half of the participants received feedback when they were within one-eighth of an inch within the target, the other half received no feedback. PRACTICE Both groups of persons drew the same number of lines, but only the persons wo received feedback improved with accuracy over time. Feedback about performance is what researchers in the field call knowledge of results, and is critical to the effectiveness of practice  ACQUIRING SKILLS Law of diminishing returns/power law of learning: with extended practice, the amount of time required to perform a skill decreases at a diminishing rate This law hold for both perceptual motor skills and cognitive skills Each additional practice session after the first trial produces smaller increases in performance. Learning occurs quickly at first, but then gets slower  So this law provides a good description of how practice can generally affect performance, however there are ways to overcome these practice effects Practice effects can be overcome by incorporating feedback on performance In one experiment a participant was required to kick a target as rapidly as possible where feedback was provided on the rate at which he was able to kick the target, and the ACQ UIR ING rate at which he was able to decrease the time required to SKILLS kick the target. Once diminishing returns stepped in and he was no longer able to reduce the speed taken to kick the target, he was given feedback by way of a video where he was able to observe movements required to minimise kicking time. This is observational learning. The participant forms a memory of the kicking movements observed which he then uses to enhance his performance  ACQUIRING SKILLS Incorporating feedback requires that the actual feedback will maximise the benefits of practicing the skill Some experiments have shown that frequent feedback on perceptual motor skills lead to good performance in the short term but mediocre performance in the longer term while infrequent feedback leads to mediocre performance in the short term but better performance in the long term Information that precedes our attempt at learning a skills is also critical to performance, such as viewing instructional videos  Developing a skill also depends on the way the skill is practiced. Concentrated and continuous practice improves performance in the short term, and ACQUIRING this is called massed practice SKILLS On the other hand, if we space out our practice over several sessions it leads to better retention in the long term and this is called spaced practice  Implicit learning is learning that takes place which we are not aware of Many skills can be learned implicitly such that we may not be able to recall the range of skills we have acquired under this method There are two ways in which implicit learning IMPLICIT occurs LEARNING Incidental learning This occurs when a person continuously performs a task and stumbles on a strategy to improve performance of the task This method of learning is tested by researchers through the use of serial reaction time tasks  The second type of implicit learning is with patients with anterograde amnesia These persons cannot form new memories They can learn complex skills but have no memory of performing the task previously IMPLICIT Evidence of learning is seen in the LEARNING improvement in performance over time It is not the same type of implicit learning seen in patients without memory deficits, however, neuropsychologists refer to this learning as implicit because the patient is essentially learning in the absence of any conscious awareness of learning  Our skill memories are affected by a number of things: How well the skill memory is encoded How often it has been recalled The conditions in which recall is attempted Retention of perceptual motor skills are better retained than cognitive skills but they are RETENTION subject to deterioration AND Examining forgetting of skills is a bit more challenging that examining forgetting of events FORGETTING or facts because it is difficult to determine whether the person has forgotten how to do the skill or if the person has lost physical control Reliable evidence of which may be the reason comes from observation of neural activity during performance and non-performance of skills  The loss of skill through non-use is called skill-decay Skill decay follows a similar pattern for forgetting memories of events and facts Most forgetting of a skill occurs right RETENTION after its last performance and the incremental forgetting over time AND decreases FORGETTING Forgetting can also occur because of interference: where new memories interfere with skill memory previously learned This occurs outside of our conscious awareness  There is no subjective way for persons to know if forgetting is due to interference or the passage of time Students who learned a finger tapping task demonstrated enhanced performance following a period of sleep RETENTION If they learned 2 sequences in one day, sleep enhanced performance only improved the AND second sequence of learned movements FORGETTING If the learned 2 sequences on separate day, sleep enhanced performance for both sequences If they reviewed the first days’ sequence before learning the second sequence, sleep enhanced only the second sequence  Practicing two skills on the same day causes interference of the learning of the RETENTION first skill, and if a skill is reviewed on the AND same day that a new skill is the learned, there is also interference effects FORGETTING This demonstrates the fragile nature of newly formed skill memories  TRANSFER OF TRAINING Skills are highly constrained in how they are applied and is some cases, skills can be so specific that additional informative cues can disrupt performance For example, participants were trained to use a stylus without visual feedback; their performance became worse when they were given visual feedback The restricted ability of some learned skills to specific situations is known as transfer specificity  TRANSFER OF TRAINING Thorndike proposed Identical Elements Theory to explain transfer specificity This theory proposes that the transfer of learned abilities to novel situations depends on the number of elements in the new situation that are identical to those in the situation in which the skills were encoded Applying a skill memory to novel situations requires generalisation We are unsure how generalisation occurs or what factors limit generalisations Identical elements theory does not stipulate what are the elements of skill memory or how to assess the similarities and differences between those elements MODELS OF SKILL MEMORY  Practicing a skill means that we want to have a controlled and effortless performance Practice can eventually seem like skill performance is automatic and we incorrectly label it a reflex MO TOR A reflex is an innate physical response while skills PROGRAMS are something we learn AND The series of motor movements that we do are RULES called motor programs which are either inborn or learned To determine whether a skills has become a motor program, we could remove the stimulus during the action and evaluate the sequence and the results  MO TO R PRO G R AMS AN D RULES Cognitive skills, with practice can become automatic as motor programs Solving the tower of Hanoi puzzle is a cognitive skill, but with practice it can become a motor program because we learn the sequence of movements to solve it When we learn a new skill we follow a set of instructions When we have to perform the skill again, we most times recall from memory what the steps were the first time This shows that skill memory can be a memory of events and facts S TAGES OF ACQUISITION Fitts’s Three Stage Model of Skill Learning Cognitive Associative Autonomous Stage Stage Stage We first learn a skill by going through a period of acquisition where we encode information about a skill This is done through observation, trial and error, instructions or a combination of all This stage requires a great deal of cognitive effort to encode the skill hence it is called the cognitive stage  In the associative stage we rely on stereotyped actions to perform tasks and rely less on recalled memories of rules At this stage, the brain has encoded specific combinations of movement and is recalling them as needed STAGES OF At the autonomous stage, the skill and components of the skill become motor ACQUISITION programs. Motor movements must be rapid and effortless, it is almost impossible to verbalise the specific actions of the sequence of movements and performance is less dependent on verbalised memories for events and facts BRAIN SUBSTRATES  BRAIN SUBSTRATES All movement require coordinated muscle activity The brain stem and spinal cord play a critical role in movement which means they are involved in controlling and coordinating the movements necessary for skill memory We also rely on our senses when we learn skills, so the sensory cortices are also involved in processing information that contributes to skill learning  The basal ganglia is a cluster of neurons located in the base of the forebrain and receives a large number of inputs from cortical neurons The cortical neurons provide information about our sensory experiences The basal ganglia sends outputs to the thalamus which BASAL affects the interactions between neurons in the GANGLIA AND thalamus and motor cortex and to the brainstem The basal ganglia modulates motor control units and SKILL therefore plays a role in initiating and control LEARNING movements but not the formulation of the memories for events and facts Practicing a skill can change how the basal ganglia circuits participate in the performance of that skill, and due to synaptic plasticity, there would be changes in the basic neural mechanisms facilitating these changes  To understand what happens in the basal ganglia when we learn new perceptual motor skills, experimenters trained rats to run a T shaped maze where a tone was sounded to instruct the rat to make a right turn NEURAL Four basic patterns of neuron activation: ACTIVIT Y a) Some neurons fired mostly at the start AND when they were now released into the maze. PERCEPTUAL b) Some fired most when the instructional MOTOR SKILL tone was sounded Some fired most when the rat turned LEARNING c) right or left, d) Some fired at the end when the rat received the food.  N E U R A L AC T I V I T Y A N D P E RC E P T UA L M O T O R SKILL LEARNING In the early stages of learning, most of the recorded neurons showed one of these 4 patterns of activation. Most of the neurons fired when the rat turned right or left, and there was also activation in ways that were not clearly related to the rats’ performance in the maze. As the rat’s performance improved, most of the neurons were activated that showed task related activity. They fired mainly at the start and end of the maze. These changes in neuron activity in the basal ganglia reflect changes due to perceptual motor skill learning and these changes are consistent with encoding and control skills necessary for the activity.  Neuroimaging studies show that the basal ganglia is activated during cognitive skill learning BRAIN Using a classification task, participants are to decide from cards shown with unique patterns ACTIVIT Y of shapes and colours, what the weather would DURING be like, i.e., rainy or sunny COGNITIVE There is no simple rule to follow so participants learn through trial and error and SKILL the computer decides whether the response is LEARNING correct The basal ganglia was active during learning on this task Despite its activation, its specific function in learning of cognitive skills is not known  CORTICAL REPRESENTATION OF SKILLS Most animals do not have a cortex, and those that are born with one can make several movements after surgically removing their cortical neurons Mammals are the only animals that make extensive use of cortical regions for any purpose, so whatever its role in skill memory, mammals are the ones that rely on this. The neural circuits in the cortical regions that are active when you engage in movement change over time in ways that would enhance your movement. The areas of the cortex that is engaged when we perform a specific skill actually expand while areas that are not relevant to the performance of the skill show no or fewer changes  CORTICAL REPRESENTATION OF SKILLS The movement that causes these changes are very specific Cortical expansion is indicated by increased blood flow after extensive practice, increased grey matter, which is an indication of more neuron activity The evidence of cortical expansion was also observed in electrophysical studies with monkeys. In this experiment monkeys were trained in a tactile discrimination task. They were trained to detect a particular stimulus which was a vibrating surface at a fixed speed on its finger tip. This stimulus served as a standard. In the trials, the monkeys were given fruit juice if they correctly recognised the difference in the tactile stimulus presented. Once they recognised the difference, they were to release a handgrip. Over several trials, where the monkey learned to respond correctly to the stimulus that lead to the delivery of juice, the area of the somatosensory cortex that processed the cue increased. Cortical representation of the finger used to inspect the tactile stimuli increased.  CORTICAL REPRESENTATION OF SKILLS Perceptual motor skills also cause changes in the motor cortex Experiments where monkeys learned to turn a key using their forearm showed that there was cortical expansion in the cortical representation of the forearm It is not known how may different areas of the cortex are modified for a particular skill, but it’s a safe assumption to make that the cortical networks that contribute to the performance of the skill are modified as performance improves. It is also not known how cortical expansion occurs and what exactly it consists of but, one guess by neuroscientists is that the expansion reflects strengthening and weakening of connections within the cortex resulting from cortical plasticity  THE CEREBELLUM The cerebellum is one of the most basic neural systems involved in encoding and retrieving skill memories Input to the cerebellum comes from the sensory systems or the cerebral cortex and most output go to the spinal cord and to motor systems in the cerebral cortex Lesions to the cerebellum impair performance of motor sequences Brain imaging studies of the systems involved in motor learning showed an increase in activity in the cerebellum when humans start to learn to perform sequences of finger movements. Changes in the cerebellum have been found to be associated with skill learning and not just movement. This was observed in acrobatic rats compared to rats who were trained to run in a wheel. The cerebellum is also active when we learn new movement sequences that require precise timing.  CLINICAL ▪ Apraxia ▪ Huntington’s Disease PERSPECTIVES ▪ Parkinson’s Disease  Apraxia is a condition in which a person has challenges with coordinating skilled movements. It usually occurs from trauma to the head or if there is an interruption of blood supply to neurons Patients with apraxia can mimic the individual movement steps of a sequence but APRAXIA they are unable to combine them into a fluid sequence of movement when instructed to do so. They understand what they are being told to do or asked to do, but they just cannot comply. Apraxia can affect the ability to perform both cognitive skills and perceptual motor skills  One hypothesis is that persons with apraxia have difficulty performing skills because they cannot access the memories of how to perform the actions required for the skill. Initial research on patients who could not repeat observed gestures found that APRAXIA they could not identify when certain actions were made by others which supports the hypothesis that it is more than just losing the ability to perform an action but they have lost access to memories of the action.  HUNTINGTON’S DISEASE Huntington’s disease is an inherited disorder that causes gradual damage to the neurons across the brain especially in the basal ganglia and cerebral cortex. There are associated psychological problems like mood disorders, hypersexuality, depression and psychosis. These patients have a number of memory deficits, some of which affect skill memory, but they are capable of still learning new perceptual motor skills and cognitive skills but at a much slower rate than healthy persons. They experience additional challenges in performing tasks that require planning and sequencing. Some of the deficits in perceptual motor skill learning seems to be related to problems with retrieval of the memory of how to perform the skill and decreased storage capacity. In these patients, it is difficult to determine to what extent deficits in learning of perceptual motor skills are a direct result of cortical or basal ganglia damage as opposed to being a side effect of the person’s inability to move normally.  PARKINSON’S DISEASE Parkinson’s disease is a nervous system disease which disrupts the functions of the basal ganglia and progressive deterioration of motor control. The cause of Parkinson’s is a reduction in the number of neurons in the brainstem that modulates the activity of the basal ganglia and the cerebral cortex These patients show increasing muscular rigidity and muscle tremors and have general impairments in initiating movements Because the basal ganglia and the cerebral cortex are affected, there are some similarities in the motor deficiencies of patients with Parkinson’s and Huntington’s Disease however, persons with Parkinson’s can still learn some skills which persons with Huntington’s cannot. This points to the fact that despite similar areas being affected the impairments are different with some overlap between the two diseases. End of Lecture 8