PSY270 Lecture 5 + Chapter 6(pg 148-154) & Chapter 7
Recap of memory system: things we did not cover
-it is a separate, limited short-term memory storage component for visual/spatial information
-part of the working memory that holds and processes visual and spatial information.
-children demonstrate a visual similarity effect ( analogous to rhyming effect) while adults demonstrate
a visual similarity effect under articulatory suppression.
-This is the control centre for WM- this is where the processing goes on
often considered an attentional control mechanism
-Accesses and coordinate information from “slave system”
theory that 2 ‘slave system’ are responsible for short-term maintenance of information and a
central executive is responsible for the supervision of information integration and for coordinating the
1 slave system is the phonological loop and the other one is the visuo-spatial sketchpad.
-Does not have any storage capacity itself
-an important function for CE is regulating relevant and irrelevant information
-People with high working memory capacity are better able to inhibit irrelevant information
-Prefrontal cortex is linked to CE function and attentional control
found by Posner & Rothbard; the link between PFC and executive attention
-PFC is active during Stroop task and Wisconsin Card sorting test.
-Patients with frontal lobe damage demonstrate preservation on WCST(winsconsin card sorting test)
-Temporarily holds information from a variety of sources across space and time
binds information from other system
-It is a limited capacity buffer
-Controlled by central executive
Working Memory – RECAP
Multi-store memory system
Central control of stored material
Varies with individual
4+-1 according to Cowan
Active manipulation keeps information continuously available
Managed by central executive/attention Memory Processes
-A patient named Jimmy G, who is a war veteran suffers from Korsakoff’s syndrome
Korsakoff’s synsdrom is a condition caused by prolonged deficiency of vitamin B1, usually as a
result of chronic alcoholism; leads to destruction of areas in frontal and temporal lobes and thus leads
to memory impairment
Has anterograde amnesia and retrograde amnesia.
-Memory involves 3 stages
*duration and capacity(STM/WM = short, LTM=long)
STM: Encoding and Storage (Review)
-Storage: STM stored primarily acoustically, can be coded visually and semantically
Stored in the same code as its encoded for a short time but can be maintained via rehearsal
Attention transfers info from sensory memory to STM
-How do we retrieve the items we’re holding in STM?
serially or in parallel?
Self-terminating or exhaustive?
-self terminating = stop looking once you find it in your STM.
-Exhastive= you keep looking through all of STM even if you found it already
-Sternberg(1966) developed a technique to answer these questions
-it is a method to determine how information is retrieved from short term memory
-it involves the manipulation in presence of absence of target(letter) and set size(set of 1-6)
asked to memorize the list of numbers and after putting them into memory, probe number is
Subjects are then tested on their reaction-time according to the probe number which can be
numbers in the list or a new number.
-Found that Reaction-time grow linearly with increase in memory set size
-Found that absent trials and present trials have the same reaction time, suggesting that absent
response can only be made after all items in the STM have been searched; as a result, with a self-
terminating search, one would expect present trials to be faster, but the data contradicts this hypothesis. Sternberg search possible outcomes (where x = set size, y = response time; blue/brown red = present,
-Serial = time increase with larger set size. -Parallel = same amount of time to look at 1 -6 items.
Size doesn’t matter
-Serial self-terminating = people take longer -serial Exhaustive = always searching through all times
when target is absent vs. Present. Have to look
through it again if target is absent ( double check)
-overall, in Stenberg search, reaction time increased as list length increased
-reaction time for present and absent trials was appxoimately the same
-data suggest a serial exhaustive search.
-2 theories of forgetting from stm
Decay – if theres no rehearsal, we forget
Interference – info still there but other info gets in the way of retrieval
-Retroactive interference (RI): inhibitory effects of new information on old information
-Proactive interference(PI): Inhibitory effects of old information on new information
Serial Position Curve
-explains that memory is better for words at the beginning of the list and at the end of the list than for
words in the middle.
-Primacy Effect Superior memory for stimuli presented at the beginning of a sequence
Reason: participants had time to rehearse these words and transfer them to LTM
-Recency Effect Superior memory for stimuli presented at the end of a sequence Reason: most recently presented words would be on the STM
- evidence that primary and recency effects involve separate memory systems comes from observation
that we can eliminate one with the other
-Poor memory for items in the middle can be explained by decay theory and interference theory
-Serial recall task eliminates recency effect *by the time you get to increase the delay between hearing
list and recall*
-How they are interfered:
Items at the beginning are being interfered with items at the end.
Items at the end interfered by items at the beginning (proactive interference).
items in the middle receive retroactive and proactive interference
Release from PI(proactive interference)
-proactive interference occurs when information that was learned previously interferes with learning
-Release from PI that occurs in the Wicken’s experiment depends on the words’ categories(fruits,
profession). Because placing words into categoties invovels the meaning of the words, the results of the
Wickens experiement demonstrate that operation of semantic coding in STM
In wicken’s experiment, there were 4 groups where the first 3 groups were related to food
such as vegetable, meet, fruits. The last one was about profession.
It showed that the experiment wit the last group had the fastest recall due to no proactive
inference: profession is a different category
*Suggest STM can be stored semantically
Long Term memory (LTM)
- STm and LTM can be distinguished by comparing teh way information is coded by the two systems
-Just like STM, LTM can also be involved in auditory, visual, and semantic coding
Although all three types of coding can occur in LTM, semanting coding is the predominant
type of coding in LTM
-Semantic coding is illustrated by the kinds of errors that people make in tasks that involve LTM
example: misremembering the word tree as bush would indicate that the meaning of the
word tree(rather than its visual appearance or the sound of saying “tree”) is what was registered in LTM.
-The capacity for LTM is not known ( maybe its limiteless)
-Researchers are interested in how LTM is organized and how we retrieve memories from it LTM
-We organize information by subjects.
If LTM is very organized, it’ll be easier to retrieve. LTM: Encoding
-Rehearsal allows the transfer of information from STM into LTM
-2 types of rehearsal
maintenance: Keeps information active in STM. Helps maintain information in STM/WM, but
its not an effective way of transferring information into long-term memory.
-ex. Rehearse a telephone number without consideration of meaning or making
connection with other information
Elaborative: Links info from STM with that already in LTM. More effective at transferring
information into LTM
-occurs when you think about the meaning of an item or make connection between the
item and something you know.
Levels of Processing
-Levels of processing theory describes how memory depends on how information is encoded, with
“deeper” processing resulting in better encoding and retrieval than “shallow” processing.
In other words, memory depends on how information is programmed into the mind.
-Craik and Lockhart proposed the idea of levels of processing.
In their test, they tested for how memory is superior when a meaningful connection has been
made between an item and something else compared to not making the connection
Found that its true thus, the levels –of-processing theory states that memory depends on the
depth of processing that an item receives.
-Depth of processing: this is described by distinguishing between shallow processing and
-Shallow processing: involves little attention to meaning.
Occurs when attention is focused on physical features such as whether a word is printed in
lowercase or capital case or the number of vowels in a word.
Can also occur during maintenance rehearsal, in which an item is repeated to keep it in
memory but without consideration its meaning or its connection with anything else.
-Deep processing: involves close attention, focusing on an item’s meaning and relating it to something
considers how an item might be useful in a particular situation or creating an image of the
item in relation to another item would create deep processing.
This way of processing an item occurs during elaborative rehearsal and results in better
memory than shallow processing
-Memory is a by-product of the level at which information is processed at encoding
deep, meaningful processing leads to long-lasting memories
Shallow, sensory processing is easily forgotten
why? Elaboration and distinctiveness.
-Elaboration = linking info between STM & LTM
Creates meaningful links to LTM
ex. Milk and butter= dairy, apple= fruit -Distinctiveness = how unique is that info
different from all other memories in LTM
One cue tells us exactly where to find information
ex. Not just fruit, its red fruit you pick during the fall
LTM: Retrieval and Forgetting
-Decay and interference can occur in LTM as well as STM
-Retrieval from LTM is highly related to encoding
-Mnemonists use effective encoding strategies to increase LTM dramatically
-Forgetting from LTM is often caused by retrieval failures
information is available but not accessible
-thus, when we talk about retrieval failure= info is there but fail to access it
ex. You cant answer a question in the exam but you remember how to afterw