Psychology Chapter 7 - Memory
H.M. - unable to form long-term memories. Able to remember everything before the
surgery. Can learn motor tasks but be unaware of it.
Modal Memory Model - (Standard)
Sensory input -> sensory memory -> Short-term memory -> Long-term memory
(unattended info is lost) (unrehearsed info is lost) (some info lost over t)
Sensory Memory - iconic memory and echoic memory. George Sperling experiment 3
flashing rows of letters for brief moments, brief periods of delay follow, and asking to
recall. Only able to recall within 1/3 second, after which sensory-memory trace faded
and was no longer accessible.
- Iconic and echoic memories let us experience world as continuous stream rather
than discrete sensations
STM - (immediate memory) fleeting thoughts, feelings
- Limited capacity, holds information in awareness for a brief period of time.
- Computer analogy is RAM, constantly replaced by new info, lost if not saved
- Holds info for 20 second limit. Disappears if not rehearsing it. (telephone #)
- By 18 seconds of counting backwards, people have poor recall for consonants.
Because of interference from previous items in STM
Memory span and chunking
- Limited to about 7 items (plus or minus 2, George Miller) called memory span.
o Recent work says four units
o Varies among individuals, some IQ tests use this as test of intelligence Psychology Chapter 7 - Memory
- String of letters easier to remember when separated into meaningful words
1) memory span is limited to 7 items, but items can be letters,
numbers, words, or even concepts
2) Chunking - breaking info into meaningful bits easier to
remember. Chess players able to memorize scenarios.
Efficiency of chunking depends on long-term memory
STM is NOT a single storage system. It is an active processing unit deals with multiple
types of information such as sounds, images and ideas.
- 3-part active system called working memory(Alan Baddeley) - keeps info
available for activities such as problem solving, reasoning, comprehension. e.g., HM
can keep track of a conversation as long as hes actively involved in it.
- 3 components: central executive, phonological loop, visuospatial
central executive the boss. interactions between subsystems and LTM, encodes
info from sensory system and filters important info to be stored in LTM. Relies on two
- phonological loop - encodes auditory information. inner voice. Active when you read,
speak, or repeat words to yourself. Words are processed by sound not by meaning.
Experiment that people tend to make errors with consonants that sound alike rather
than look alike (G and T, rather than Q).
- visuospatial sketchpad - processes visual info. Features and location. Psychology Chapter 7 - Memory
Because separate systems, people with brain damage might have difficulty
remembering spatial layouts but not words or vice versa.
- computer analogy: hard disk
- human LTM is limitless
LTM is different from STM in two ways: duration and capacity.
Different systems or not? Evidence came from research at individual level (recall long
lists of words)
- ability to recall items on list depend on ORDER of presentation, those presented
early or late better remembered than those in middle called serial position effect
- Divided into two different effects
- primacy effect - people remember items that were presented first
because they rehearsed them more and they went into LTM
- recency effect most recent, last items are still fresh in the STM.
SO primacy effect due to LTM, recency effect due to STM. Experiment: when delay
between presentation and recall task, interferes with recency effect, not primacy effect.
HOWEVER recency effect not entirely STM. Lasts longer (remember last class) and by
itself does NOT prove that STM and LTM are really different types of memory storage.
BEST support for distinction of STM and LTM? Biological level of analysis in case
studies such as H.M.
- His STM and LTM are intact, but is unable to transfer new info from
STM into LTM. Psychology Chapter 7 - Memory
- Other case, poor STM but ok LTM. Normal flow of info was getting
So LTM can be dissociated from STM, but the two systems are highly interdependent.
Example: to chunk info in STM, need to form meaningful connections based on LTM.
What gets into long-term memory
1) Info enters permanent storage through rehearsal
Distributed practice is much better than massed practice (cramming). Overlearning
(rehearsing material you already know well) is recommended. Studying for shorter
periods of time but spreading study sessions out over several days or weeks is most
efficient way to learn.
2) Only meaningful information - info that can help us adapt to environment - can go
into LTM. To benefit from experience.
a. Evolutionary theory explains how we decide in advance what info will be
What are the different memory systems?
Long-term memory is not a unitary system, its different systems encode and store
different types of information in different ways. e.g., ability to ride a bicycle and recite a
- In order to distinguish memory systems, important to know if
reference being made is PROCESS or CONTENT of memory.
- Most basic distinction is memories for which we consciously
remember and use information and those for which occurs without