6. Forgetting Flashcards
Seven sins acronym
The Absolute Best Memory System Brings Problems
Transience (forgetting)
Due to time or interference
Describes the levelling off of the forgetting curve at long delays, beyond this memories appear impervious to further forgetting
Permastore
Bahrick
Permanent memory store, things must be transferred here within 2 years
For example forgetting a foreign language stops after about 2 years, what you remember then you will always remember
Similar to consolidation
Forgetting curve
Steep initially- maybe due to weakened memories during consolidation??
Eventually levels off… Permastore
Josts law
If 2 memories are equal strength but A is older than B… The oldest will become stronger and more robust in a given time frame
This is because the slope is much less steep for A in a given time frame so there is less forgetting that can occur
Half life
Half life of a memory trace reflects the strength of initial learning
Greater half life = stronger encoding and less prone to interference
Accelerated forgetting
Patients with temporal, lobe epilepsy show increased long term forgetting and a greater rate of forgetting
Decay
Loss of availability rather than accessibility
The wasting effects of time, gradual weakening of memories
Decay when they are not used
- time based resource sharing model… Info decays until we can refresh it again through rehearsal or attention
Particularly important in WM where memories must be kept active
DIFFICULT TO ISOLATE FROM INTERFERENCE
Criticism of decay theory
McGeoch
Items not recalled, can be recalled later
Forgetting is determined by number or density of events during retention
Forgetting is higher after waking than sleep
Retroactive interference
New memory trace interferes with an older memory trace
Reduces availability of the old trace rather than pushing it out- competition at retrieval
Useful for updating knowledge!
Proactive interference
An old memory interferes with a new memory
Eg calling new be by old bf’s name
Two factor interference theory
- Unlearning = earlier representations are weakened
2. Response competition= earlier representations remain but there is competition at retrieval
Increasing proactive interference
Similar learning experiences (shared cue)
If there are multiple targets for 1 cue there are multiple route that could be taken and therefore increases the risk of error.. Following the wrong path
Interference and amnesia
Amnesia patients given memory task then either wakeful resting or a distracting task
Wakeful resting aided recall
Distractor meant they remembered nothing- very susceptible to retroactive interference
Decay and interference
Hpc is resistant to interference, good at distinct pattern remembering and keeping events separate. More likely to suffer from decay.
Neocortex is not good at pattern separation so more likely to suffer from interference
Amnesic patients lack hpc, so they are unable to store events as separate, so suffer more from interference
Recollection and interference
Recollection is driven by the hpc so is resistant to interference and suffers from decay
Hpc supports episodic memory which binds memories in spatial-temporal context so they are distinct events
Familiarity and interference
Non hpc areas so more likely to suffer from interference as cannot keep memories distinct
Cues improve…
Accessibility
Recognition vs recall
Recognition is generally superior to recall
Due to presence of retrieval cues
Can accurately respond on basis of familiarity rather than knowing required for free recall
Blocking
Tip of the tongue phenomena 20% young adults Occurs more with increased frustration Reduced by recognition Due to limited speech activation?
Missattribution
Source memory confusion
Consequence for eyewitness etc
Remembering something that they didn’t really experience
Suggestibility
Memory is liable to distortion and error as a result of suggestion
Eg presenting false photos and asked for description of the memory
Similar to Missattribution- only suggestibility MUST have the presence of suggestion
Bias
Schemes and long term knowledge of the world can influence and district memory
Constructive nature of memory
Memory has a positivity bias- likely to remember more positive events
Confabulation
Clinically significant false statements that are made without the intention to deceive
Clinical feature of Korsakoffs amnesia
Problem ends with memory and control mean that patients construct memories to replace those that are missing to make sense of the world
Qualities very similar to real memory
Persistence
Cannot forget memories
Hyperthymestic syndrome= unusual, superior autobiographical memory
Why forgetting is useful
Update knowledge Forget horrible events Prevents mental clutter to allow focus on relevant stimuli Free up resources Exact record of the past is useless
Efficiency of memory
Evolved to be of optimum use
Huge capacity
Ability to think flexibly
Utilise and manipulate knowledge for new situations
Costs for memory are fallibility
Seven sins of memory
Transience Absent mindedness* Blocking* Miss attribution* Suggestibility Bias Persistence
- forgetting
Rate of forgetting
Fast in amnesics
Slow in AM
Slow in implicit memory
