Psych Week 9: Memory
Memory: the fundamental cognitive mechanism that allows us to store and retrieve info.
Metaphors of memory:
O Acts like a video camera which accurately preserves images and audio to be played back
at a later time
O Acts like a filing cabinet – we create memory files that are stored in an organized folder
system, which can be accessed to remember something.
Frederic Bartlett realized that all of these have something in common. While each does provide a
useful way of thinking about memory in some regard, they are misleading. Each assumes that
memory can store experiences in their original, undistorted form and that memory retrieval is a
The Basics of Memory:
Memory Acquisition: what will be stored in memory?
Memory Storage: how and where will it be stored?
Memory Retrieval: how can memories be returned to consciousness?
Cue-response: studied by behaviourists, one memory acts as a cue to trigger another memory.
Early researchers of memory were heavily influenced by the behaviourists, so it’s not surprising
that early focus of memory research concerned how cues interact with encoding and retrieval
mechanisms of money.
Hermann Ebbinghaus operationally defined memory as a serial learning task.
O As he memorized word lists, he suggested that each word in the list served as a cue that
triggered the memory of the word that followed.
Cuing is an important concept in encoding specificity, a phenomenon by which encoding and
retrieval are linked through cues.
Psychologists rely on cognitive models to understand complex cognitive function, like memory.
Models describe and organize data and most importantly, make specific, testable predictions
that can be studied in controlled experiments in the lab.
The basic memory task involves two phases.
O During the encoding phase, a subject learns a list of items, words, or pictures.
O Recall test: subject is asked to freely generate as many items as she can remember.
O Recognition test: subject is shown several items and asked to judge whether each item
is “new” or “old”
O In experiments, those who are explicitly asked to learn the list of presented items
perform better than subject who are distracted and unexpectedly given a test.
Ebbinghaus performed test using non-sense words. One of the research questions that
interested him was how long memories could be maintained.
O He found that if he took the test immediately after he learned the words, he was able to
recall more than when he waited to take the test. This helped him to construct the
The Multi-Store Model
Multi-store model proposed by Atkinson and Shiffrin in 1968.
Assumes that memory is composed of both short and long-term storage systems.
Incoming perceptual info is first stored in a short-term memory buffer. In a sense, the short term
memory buffer operates in a similar manner to RAM on a computer; info in short term memory
is available online for tasks but is not stored permanently.
Important info in short-term memory can be transferred to long term memory. Miller demonstrated that for most short-term memory tasks, people can remember about 7, plus
or minus 2 items. Any more than that, and the demand on the short-term memory becomes
strained. If rote rehearsal stops, the short-term memory can fade.
Miller discovered that people can reorganize or “chunk” info into meaningful packets allowing
for more info to be stored in short-term memory.
Letter grouping that form words, pack even more info into a single chunk.
The power of cognitive model in general, and the Multi-store Model of Memory in particular, lies
in their ability to make testable predictions about how memory works.
The Serial Position Curve
Memory performance is often best for items early or later in the list and worst for items in the
middle of the list.
O Summarized in the serial position curve.
Primacy Effect –memory performance is good for items encoded early in the list.
O According to the multi-store model, the items at the beginning of the list will be the first
to enter our short-term memory, and thus have the most opportunity to be rehearsed.
O Memory rehearsal is good because the have entered the long-term memory.
O Items in the middle of the list have less opportunity to be rehearsed and therefore less
opportunity of being transferred into long-term memory.
O Recall for later items on the list is also good even though there is less time to rehearse.
O Recency Effect; all encoded info is first sent to the short-term memory buffer that is
limited to hold about 7 items.
O The newer items replace the older items in the short-term memory buffer. However the
last 7 items are not followed by anything and therefore are not replaced so they are still
active in the short-term memory storage system.
If rehearsing drives the primacy effect, then the primacy effect should be influenced by a
manipulation that changes a subject’s ability to rehearse items?
O Can be tested by manipulating the presentation time of each to-be-remembered item.
O The primacy effect should be enhanced for a list of items given with a long interval of
presentation relative to a list of items given with a short interval of presentation.
If the Recency effect is driven by items remaining active in the short-term memory buffer, then
the Recency effect should be influenced by any manipulation that affect the content of the short-
term memory store.
O The Recency effect disappears for the distracted group, but remains intact for the
The serial position effect is a robust finding in memory research that is handed well by the multi-
store model, which makes testable predictions that can be studied under controlled lab settings.
The Levels of Processing