Cognition Lecture 4

Cognition Lecture 4

1. Forgetting

   • Types
     • Incidental forgetting - occurs without the intention to forget
     • Motivated forgetting - purposefully diminish access to memory
   • Superior autobiographical memory
     • Uncontrollable remembering
     • Automatic, effortless, not under conscious control
     • Cannot forget unpleasant memories - can be distracting
   • Forgetting rate
     • Increases as time progresses but rate is different
     • Ebbinghaus forgetting curve - logarithmic curve
       • Forgetting rapid initially
       • Less additional forgetting at longer intervals
     • Meeter et al. (2005) - recall for public events dropped from 60% to 30% in a year
     • Bahrick et al. (1975) - recalling a name when giving a person's picture impaired similar to forgetting curve
     • Bahrick (1984) - forgetting of foreign languages levelled out after 2 years.
   • Availability vs Accessibility
     • Availability - item may not have a memory trace anymore
     • Accessibility - the item may be stored but not accessible
   • Factors that Discourage Forgetting
     • Better learning
     • Testing effect (Linton, 1975)
     • Jost's Law - all else equal, older memories are more durable and forgotten less rapidly than newer memories
   • Consolidation
     • Transforms new memories into a more permanent state that is resistant to disruption
     • Synaptic Consolidation
       • Structural changes in the synaptic connections between neurons
         • May take hours - days - vulnerable until completed
     • Systems Consolidation
       • Gradual shift of memory from hippocampus to cortex - replayed until linked
         • May take months-years - vulnerable when in hippocampus

2. Causes

   • Trace Decay
     • Memories gradually weaken because of time
     • How?
       • Memory's activation fade (inaccessible)
       • Memory itself and elements degrade (unavailable)
     • Biological basis
       • Synaptic connections degrade and neurons die over time
       • Neurogenesis - growth of new neurons means connections modified - degrade older memories in hippocampus
     • Validity
       • Behaviourally difficult to prove - cannot control rehearsal and interference
       • Unable to tell if unavailable or inaccessible
   • Correlates of Time
     • Forgetting caused by correlates of time
     • Contextual fluctuation
       • Incidental context differs between retrieval and encoding over time
       • Incidental context less similar to remote past than recent past
     • Interference
       • Similar traces impede retrieval
       • Competition assumption - memories associated to a shared cue automatically impede retrieval
         • A cue activates all associates - compete for access to consciousness - hinder target memory
       • Retroactive Interference
         • New memory impairs recall of old memory
         • Experience needs to be similar
         • Baddeley and Hitch (1977) - new rugby games interfere with previous ones - making them less accessible. Due to interference rather than decay
       • Proactive Interference
         • Old memory impairs recall of new memory
         • More severe for recall than recognition
   • Other Causes
     • Part-Set Cuing Impairment
       • Recall impaired by provision of retrieval cues from the same category of items in memory
       • Hints impede memory retrieval
       • How?
         • Presenting similar items strengthens association to cue
         • Competition for non-cue increases
       • Slamecka (1968) - providing cues reduced recall for the non-cued items
     • Retrieval-Induced forgetting
       • Selective/partial retrieval can harm recall of other memories related to retrieved item
       • Shawk, Bjork and Handal (1995) - interrogating people about some of the stolen items impaired memory for the related items
       • Selective retrieval may contribute more to severe forgetting for information that isn't practiced

3. Interference Mechanisms

   • Associative Blocking
     • Cue elicits a stronger competitor than target memory
     • Examples
       • Tip-of-the-tongue
       • Retroactive interference
       • PArt-set cuing
       • Cue overload
   • Associative Cuing
     • Associative bond linking to a memory trace is weakened after being retrieved in erorr.
     • Difficult to demonstrate empirically
     • Examples
       • Retrieval-Induced Forgetting
       • Retroactive Interference
   • Inhibition
     • Allows an unwanted response to be stopped
     • Forgetting targets the memory itself (not association)
   • Functional Account
     • Forgetting controls retrieval in face of competition
     • Facilitates retrieval attempts of strengthened memories - inhibiting competitors - beneficial!
       • Serves goal-directed behaviour and decision-making
     • Richards and Frankland (2017)
       • Memory guides intelligent decision-making
       • Forgetting allows flexible behaviour and generalisation to new experiences
       • Not a failure of memory but a function
       • Investment in optimal mnemonic strategy