What are the different types of forgetting?
· Incidental forgetting
- Occurs without the intention to forget
· Motivated forgetting
- Purposefully diminish access to memory (e.g. unwanted memories)
What is a superior autobiographical memory?
- Uncontrollable remembering
- Feels as though the person relives the events they remember
- Remembering is ‘automatic’, effortless and not under conscious control
- Cannot forget unpleasant memories
- Memories can be distracting
What is the forgetting rate?
- Forgetting increases as time progresses BUT the rate of forgetting is deferent
- Ebbinghaus studies on forgetting
- Forgetting curve
§ Logarithmic relationship
§ Forgetting rapid initially
§ Less additional forgetting at longer intervals
What is the distinction between availability and accessibility?
- Recall is generally worse after delays than recognition -> a distinction should be made between:
- Availability
§ Is the item in memory store? (this item may not have a memory trace any more) - Accessibility
§ Is the item accessible for retrieval? (the item may be stored but not accessible - Both may denote forgetting
What are factors that discourage forgetting?
- Better learning at the beginning
- Repeated attempts to retrieve – (testing effect/ generation effect) builds up resistance to forgetting (e.g., Linton, 1975)
§ Recalling an event reduces the rate of forgetting - Incomplete or inaccurate retrieval may lead to memory distortions
- Not all memories are equally vulnerable to forgetting at all points in their history (forgetting curve)
What is Jost’s law?
§ All else equal, older memories are more durable and forgotten less rapidly than newer memories
§ New memories are initially more vulnerable to disruption/ distortion until they are consolidated
What is consolidation?
- Consolidation: The process that transforms new memories from a fragile state, in which they can be disrupted, to a more permanent state, in which they are resistant to disruption
What is synaptic consolidation?
§ Structural changes in the synaptic connections between neurons
§ May take hours – days to complete
§ Memories are vulnerable until these changes are complete
What is systems consolidation?
§ Gradual shift of memory from hippocampus to the cortex
§ Memory components (in the cortex) are replayed until they are linked
§ May take months – years to complete
§ Memories are vulnerable for as long as they rely on hippocampus
What is trace decay?
- Memories weaken due to passage of time
Example: facts you learned in school fade out of memory
What are context shifts?
- Different cues are available now than the ones available at encoding
- Example: school is a completely different context than now
What is interference?
- Similar memories hinder retrieval
- Example: After a biology lecture you forgot what you learned in chemistry an hour before
What types of memory are especially prone to trace decay?
§ Priming and familiarity especially prone to decay
How does decay affect memories?
§ A memory’s activations fade, but the memory itself is intact (stored and available but inaccessible)
§ OR
§ The memory itself and its elements (i.e., its associations) degrade along with its activity level
What is the biological basis of trace decay?
- Synaptic connections degrade and neurons die as time goes by -> memories may die or fade in the same way
- The opposite biological mechanism may also explain decay (Frankland et al., 2013)
§ Neurogenesis (growth of new neurons – especially in hippocampus) means that the structure is remodeled and its connections are gradually modified
§ Good for new learning – generation of new associations
§ Bas for older memories retained in hippocampus
What is the validity of trace decay?
- Behaviourally it is difficult to prove trace decay
- Two important factors cannot be controlled when attributing forgetting to decay:
§ Rehearsal
§ Interference from new experiences/ memories - Memories unavailable or simply inaccessible?
What are alternative factors of incidental forgetting?
- Correlates of time
§ Forgetting may not be caused by the passage of time itself but by a correlate of time - Contextual fluctuation (correlate of time):
§ Similarity between encoding and retrieval context may explain forgetting
§ Incidental context differs more between retrieval and encoding over time
§ Incidental context is less similar to the remote past than more recent past - Interference
§ Similar traces/ memories impede retrieval
§ It is difficult to discriminate between them
§ Similar memories accumulate more over time
§ Whenever the cue that can be used to access a memory becomes associated with other memories
How does interference work?
- Competition assumption: memories associated to share cue automatically impede retrieval when the cue is presented
§ A cue activates all associates (more or less)
§ The activated associated compete for access to consciousness
§ Competitors hinder access to target memory - Interference occurs due to the negative effect of having competitors
§ It increases with the number of competitors a target memory has
What is retroactive interference?
If the target memory is based before a new memory
- Introducing a new (second) memory impairs recall of a first memory (especially similar)
- Especially strong interference if the two lists share cues
- More training on the second list results in more first list impairment
- Not every type of intervening experience impairs memory – the experience needs to be similar
What is proactive interference?
If the target memory is placed after a new memory
- The tendency of older memories to interfere with retrieval of recent experiences and knowledge
- The number of previous learning experiences (e.g. lists) determine the rate of forgetting of new ones
PI is more severe for recall than recognition
What is part set cueing impairment?
- The tendency for recall to be impaired by the provision of retrieval cues drawn from the same category of items in memory
- Providing hints may impede memory retrieval
- The impairments is more sever with increasing numbers of cues provided from the same set
- Presenting similar items as cues, strengthens their association to the cue
- Competition for non-cues increases -> memory worsens
What were the results of Slamecka’s part set cueing study?
providing cues (i.e. competitor items) reduced recall for the non-cued items (i.e. targets)
What is retrieval induced forgetting (RIF)?
- Selective/ partial retrieval can harm recall of other memories related to the retrieved item
- Compared to baseline items for which no related items had been retrieved
- This has important implications for learning and studying
- Selective retrieval may contribute to more severe forgetting for information that is not practiced/ retrieved
What does retrieval induced forgetting (RIF) have implications for?
RIF may have important implications for how witnesses should be questioned
