PSYC105 Lecture Notes - Lecture 10: Explicit Memory, Anterograde Amnesia, Mental Calculation
1 Jun 2018
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Cognition – Week 10
Study of mental processes:
• Memory
• Attention
• Language
• Thinking and reasoning
→ Mental processes are not directly observable – understanding methodology
developed to study cognition is very important
Memory:
• This is how you know who you are
• Without memory
o There would only be a ‘now’, not a ‘then’
o No memory, no sense of self
• Multistore Model of Memory: different sections of the memory
o 1. Sensory input goes into sensory memory (capacity is large but does
not last long; unattended information is lost)
▪ Visual sensory memory is called ‘Iconic Memory’
▪ Sensory memory is in the same form as the original stimulus
▪ Sensory memory fades very rapidly
▪ Large capacity – but you can only keep it in memory for a very
short amount of time
▪ Need to select information from sensory memory and put it in
Working Memory in order to maintain it for longer periods of
time
▪ We cannot select all information as the next step has very little
capacity
o 2. Working (short-term) memory (unrehearsed information is quickly
lost)
▪ Maintenance rehearsal – important
▪ You need your attention to sub-select information to put into
working memory
▪ The active, conscious mind
▪ Visuospatial sketchpad → mental imagery
▪ Articulatory loop → rehearsing the sound
▪ Central executive → coordinates the mental activity
▪ Working memory has limited capacity e.g. ‘digit span’ test,
traditionally 7 +/- 2 items
▪ Depends how fast you can say items
▪ Also depends on ‘chunking’ – e.g. 4, 9 is ‘49’
• Grouping elements into meaningful units improves
performance on short-term memory task
• ‘Short term memory’ is affected by meaning
information in long-term memory – argues against
strictly serial organization from STM to LTM
o 3. Long-term memory (some information may be lost over time)
▪ Encoding from working memory into LTM and also retrieval
▪ Very large capacity – unlimited
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▪ Organised according to meaningful relations
▪ Memory is reconstructive
▪ Memory that can be retrieved after attention has been diverted
▪ Duration: minutes to years
• Evidence for the distinction between short and long-term memory
o Serial position effect in free recall
▪ Primacy effect → items at beginning of list are easier to
remember than those in middle
▪ Recency effect → items at the end of list are easier to
remember than those in middle
▪ Primacy and recency components affected differently
▪ Faster rate of presentation – less time for rehearsal, reduces
primary effect not recency component
▪ Filler task (e.g. mental arithmetic task) after list – becomes like
middle component (serial position not at the end) removes
recency effect
o Neuropsychological data (patient H.M.)
▪ Impaired mechanism that transfers information from STM to
LTM
• Suffered from severe epilepsy
• Surgery in 1953 to remove regions of both medial
temporal lobes, including hippocampus
• Relieved epileptic symptoms but at a cost
• Reported own age 2 years younger than he actually was
• Could not remember people he had just met a few
minutes ago previously
• Intelligence scores were fine as was language
functioning
• No changes in personality or motivation, but memory
severely impacted
• Even working memory was fine, just could not form
new long-term memories
• “Living in the permanent present” e.g. no recognition of
doctors who treated him
• Today, surgeons avoid removing temporal
lobe/hippocampus regions in both hemispheres
• Memory processes (what processes lead to more durable/long term memory?)
o Encoding processes
▪ Establishing a record or a memory trace
▪ Deeper levels of encoding produce better recall
▪ Self-reference effect: memory is especially good for
information related to ourselves
▪ Spacing effect –
• Information is retained better when rehearsal is
distributed over time
• Optimal space depends on how long you want to be
able to retain the information (the longer the intervals
between rehearsal, the longer you will be able to retain
info)
find more resources at oneclass.com
find more resources at oneclass.com
