Week 6 Flashcards
(39 cards)
JK
Symptoms of parkinsons in late 70s
Later problems with memory for familiar tasks - using doorknobs and turning off radio
Could remember daily events and facts
Problem with implicit memory - cognitive tasks outside of awareness
The cases of J.K. and H.M. demonstrate that implicit memory is functionally distinct from explicit memory.
Squire - long-term memory
Squire - long-term memory is comprised of explicit, or declarative, memory and implicit, or nondeclarative, memory.
Explicit memory is conscious while implicit memory is unconscious
Memory for facts, events, places and things that can be described
Implicit memory refers to learning that is reflected in the ability to perform a task but that cannot be articulated. Knowing how to turn a door handle or drive a car reflects implicit memory
What is the distinction between explicit and implicit memory?
Distinction is consciousness -
Consciousness is the mind’s level of responsiveness to incoming sensory information. Consciousness enhances an animal’s ability to construct a mental representation of the sensory world and select behaviours.
as the number of reflexes needed to survive in an environment increases, reflexes become less efficient, and can potentially conflict with one another
produce a single sensory representation and allow the animal to use it to choose the best response. This sustained, complex representation is what we know as consciousnes
Warrington and Weiskrantz
Compared explicit and implicit memory
People with amnesia - matched controls with a list of 5 letter words 3 times
Tested each individual using free recall
Although they had worse recall and recognition - completed word fragments with words form the study list at the same rate as controls
The observation that people with explicit memory deficits typically perform normally on tasks involving implicit memory is evidence that explicit memory and implicit memory are two separate memory systems.
Gollin Figure Test
Individuals shown a series of figures depicting an object at various stages of completion; the object is more complete each time it is presented.
The participant is asked to identify the object as soon as possible.
Typically, a person needs to see several presentations before identifying the object for the first time but can recognize the object based on more incomplete representations if the experiment is repeated
replicated in people with amnesia; although people with amnesia have no explicit recollection of having seen the figures before, they are able to identify objects with less information if they have already seen the object before, suggesting implicit memory is intact
Pursuit Rotor Task
people with anterograde amnesia - motor learning with no explicit memory of having practised a skill.
a task used to assess procedural learning where the goal is to keep a stylus on a specific spot within a rotating circle that is embedded on a disk also rotating, but in the opposite direction
Most people learn the pursuit-rotor task in about an hour.
If people with anterograde amnesia are asked to perform the task again a week later, they master it much more quickly, even though they have no explicit memory of the first learning session.
Nonspeaking animals often show evidence of explicit memory
rats are placed in an arena where there is a food reward.
waits for the rat to find the food reward and then removes the rat from the arena. Following a delay ranging from a few minutes to over a day, the rat is returned to the arena.
The rat will immediately return to the location where it last found food
This searching behaviour reflects an implicit memory of how to perform the task
dissociation in explicit and implicit task performance by people with amnesia results from differences in the level of processing
experiments that revealed that whether a participant thought about a word in terms of its perceptual features or conceptual features affected performance on recognition, recall, and word-fragment tasks
Blaxton - perceptual condition, conceptual - word with synonym, conceptual - generate a word based on a synonym and a related letter
conceptually driven tests were free recall, semantic-cue recall, and tests of general knowledge where a target word was the correct answer.
memory systems’ account of explicit and implicit memory predicts similar performance across study conditions for all explicit and implicit memory tasks and no effect for the level of processing manipulations at the time of study
Mishkin (1982
proposed a neural circuit for explicit memory that involves the prefrontal cortex, the thalamus, temporal lobe structures including the hippocampus, and the entorhinal regions at the base of the forebrain
Mishkin’s model of explicit memory, there is an interactive flow of information throughout the brain
frontal lobe damage
frontal lobe damage frequently have problems with short-term explicit memory
Damage - hippocampus and his temporal lobe
resulting in explicit memory loss.
Damage - thalamus
Chronic alcoholics often have a thiamine (vitamin B) deficiency that causes cell death in the thalamus and severe explicit memory loss known as Korsakoff syndrome.
entorhinal region damage
Alzheimer’s disease, which is characterized by a loss of explicit memory, begins with the death of cells in the entorhinal region
Mishkin - neural circuit for implicit memory
basal ganglia in the midbrain is central to implicit memory.
dopamine is thought to be necessary for the normal functioning of the basal ganglia, dopamine is associated with implicit memory formation
basal ganglia receive sensory and motor information from the neocortex, the neocortex does not receive information from the basal ganglia.
unidirectional arrangement explains why
unidirectional arrangement explains why implicit memories do not enter consciousness:
information must flow to the neocortex for an individual to become conscious of it, and implicit memories are not activated in the neocortex
Acquisition
*The learning phase during where a conditioned response is established
*Increases progressively in strength
When the dog was in front of food - drooling increased as the acquisition of the pairing became more solidified
*Works best when the CS and UCS are paired closely in time
Half a second - thorndike
Complete when the response to the conditioned stimulus is the same strength as the unconditioned stimulus
Extinction
*The reduction and elimination of the conditioned response
*Happens after the conditioned stimulus is presented repeatedly without the unconditioned stimulus
*When the behaviour no longer produces any rewards
Take away the food but continue tone - respond at the same frequency for a bit - has the connection been erased or is there something inhibiting it temporarily
Spontaneous Recovery
*The reappearance of the behavior after extinction and timeout
*Remembers the association but because time has passed, forgets the association is no longer “useful” - immediately same strength association
Savings
Faster learning of a CS-CR association following the extinction of the same association
Stop rewarding then start rewarding again
Artificial Grammars - REBER
*A set of rules governing how a string of letters can be combined
*Complex information from patterns without conscious effort, patterns learned to remain outside of an individual’s awareness
—-Algorithm decides how long the word will be and follows the steps - with random selection at each stage
–Participants were assigned to either learn and recall strings based on the artificial grammar (grammar group) or learn and recall random letter strings (control group)
–each trial the participant was presented with a letter string for five seconds and then given a piece of paper on which to record the string
–were then given feedback on which letters they reported correctly.
grammar group and the control group made a similar number of errors on the first few trials in the experiment, as the experiment progressed, participants in the grammar group recalled significantly more letters correctly than participants in the control group
Pattern-Learning Paradigms
*They are closely related to artificial grammars
As you start recognizing the pattern - get faster - tested on accuracy and speed - can’t explicitly describe the pattern - learned it implicitly
an asterisk (*) appears in one of four locations on a computer screen and the participant is instructed to press a key corresponding to the location as quickly and accurately as possible - no time for conscious processing
— follows a pattern for some and no pattern for others
NOT ABLE TO EXPLICITLY DESCRIBE THE PATTERN
Pattern-Learning Paradigms - divided-attention condition
implicit pattern-learning task. In the divided-attention condition, - location of the asterisk and then high- or low-frequency tone. - keep track of how many low-frequency tones had been presented; maintaining the tone count was intended to use some attentional resources.
found that response times in divided-attention blocks were slower than in blocks that did not include the tone-counting task and concluded that this indicated that attention was involved in pattern learning.
pattern learning involved some explicit processing, as only explicit processing involves attention
Stadler argued that the tone task made the pattern unrecognizable and that performance suffered as a result
one condition, participants completed a typical implicit pattern-learning - interval between the response to one asterisk and the presentation of the next asterisk was varied at random
second condition, participants were presented with a list of seven letters before a block of several trials. Participants had to maintain the list and report it at the end of the trial block.
third condition - tone-counting task; after each trial a tone was presented and participants had to keep track of how many times they heard a specific tone
tone-counting task would add attentional demands and would also disrupt pattern organization
final condition, a standard single-task implicit pattern-learning paradigm was used.
stadler conclusions
experimental manipulation affected pattern learning most in the random-pause condition and the tone condition and affected pattern learning least in the memory-load condition
concluded that pattern organization is critical to the implicit pattern-learning task and that the results of Nissen and Bullemer (1987) likely reflected a disruption in pattern organization, rather than attentional resource involvement in this task
