Consolidation and Forgetting Flashcards
What is Forgetting
Not a failure to encode, a failure to internalize
Memory must have been formed in order to be forgotten: problems with accessibility
May be adaptive
Ebbinghaus Forgetting Curve (1885)
Information is rapidly forgotten initially but this slows and steadies
Trace Decay Explanation
Memories fade overtime without rehearsal
Fades from phonological store (WMM, 1974)
Brown-Peterson (1958) Trigram Study
Supports trace decay theory
-P’s presented 3-consonant trigrams e.g BKK
-Count back from random number by 3
Longer time counting (delay) lowered the correct recall
0 sec delay: 90% recall
18 sec delay: 7% recall
Implications for trace decay: delay in recall means that majority of info is forgotten rapidly
Problems with Trace Decay
Time is not the only variable: account for sleep, more information is lost if interval is spent awake rather than asleep
Proactive Interference
Retroactive Interference
Proactive Interference
Old information interferes with learning new information
Retroactive Interference
New information interferes with retention of old information
Cue-Dependent Forgetting
Memories need to be retrieved with the appropriate cue to become accessible
Meeter et al (2005) MCQs
MCQ recall: 52% accurate
Free recall: 31% accurate
Answer options act as a cue
Tulving & Pearlstone (1966) found that recall doubles when given a cue
Tulving’s Encoding Specificity (1979)
Retrieval is determined by the similarities of the context of the memory and context at the time of retrieval
Memory is better when context at learning and recall is the same
Diving Study (Godden & Baddeley, 1975)
P’s learn words either underwater or on land
Recall better for words learnt under water when recalled underwater
Better recall for words learnt on land when recall is on land
2 Types of Consolidation
Synaptic: changes in connectivity between neurons, fast process
Systematic: memories become independent from the hippocampus and move to surrounding cortices
Information Storage at the Synapse
Long-term potentiation:
Enhanced firing of neuron after repeated stimulation> structural change> enhanced responding
Evidence for LTP in amygdala, hippocampus and cortex after a learning episode
Behavioural Evidence for Consolidation (Muller & Pilzecker, 1900):
-p’s learn two list of words then recall
Group 1: learn first and second list consecutively: 28% correct
Group 2: 6 minute delay between learning lists :
48% correct
Implies: learning new info straight away interferes with consolidation, 6 min delay gives time for consolidation
Physiological Evidence for Consolidation (Gais et al, 2007):
fMRI sleep study
Group 1: slept soon after learning
Group 2: slept a while after learning
fMRI showed different brain activity for each group at retrieval
