Name that tune.
Song title? Performer(s)?
R.G. Bias | rbias@ischool.utexas.edu |
1
Memory and Cognition
“The Knower”
1/26/10
R.G. Bias | rbias@ischool.utexas.edu |
2
Objectives
After this class you will be able to (it is my hope!):
- Have an (increased?) understanding of how
psychologists and information scientists develop
models of human performance
- Be able to state the differences between shortand long-term memory
- Understand how human memory and cognition
limitations influence the design of information
systems
-
Randolph – take attendance. Ask about Foss book. Ask about email about Friday.
R.G. Bias | rbias@ischool.utexas.edu |
We’re talking about “the knower”
 What do we know about humans?
 We are strong in our knowledge of
anthropometry -- the measurement of the
size and proportions of the human body.
 But these days – in “the information age” –
we are way more interested in our
cognitive selves.
R.G. Bias | rbias@ischool.utexas.edu |
On Monday, we were talking about
Sensation and Perception
 “Sensation” is the transformation of physical energy into
nerve impulses to the brain.
 “Perception” is the interpretation of – the imposing of
meaning upon – those sensations, including the
influence of beliefs, attitudes, biases, moods, . . . .
 The fact of “ambiguous images” shows the influence of
these non-stimulus (“top-down”) factors – the importance
of CONTEXT on perception.
 We (re)learned a little ear and eye physiology.
 We (re)learned that there are some cues that require 2
eyes, to help us infer depth/distance from the twodimensional retinal image (e.g., binocular disparity), and
some cues that require just 1 (e.g., interposition), some
that require motion (motion parallax).
R.G. Bias | rbias@ischool.utexas.edu |
Attention
 So, imagine the outrageous amount of sensations!
 We employ attention to allow some of these sensations
to “make it through” (i.e., come into our conscious
consideration) and filter out others.
– You aren’t paying attention to your pant leg rubbing against your
calf.
– OK, NOW you are.
 Selective attention – you focus on some sensations and
not others.
 Divided attention – you try to attend to two or more
simultaneous streams of sensations.
R.G. Bias | rbias@ischool.utexas.edu |
So, our “cognitive selves”
– Question: Can you remember a 30-digit number?
– I say that you can, right now, without practice,
seeing it only once, for 1 second, with no time to
rehearse.
R.G. Bias | rbias@ischool.utexas.edu |
3333333333333333333333333333333
R.G. Bias | rbias@ischool.utexas.edu |
So the answer . . .
 . . . to the question “Can you remember a
30-digit number?” is,
 It depends.
R.G. Bias | rbias@ischool.utexas.edu |
If you will . . .
 Help me conduct 3 memory experiments.
 This exercise will . . .
– Demonstrate experimental psychological
methods
– Illustrate models of human memory
– Help me get a publication in a journal!!
R.G. Bias | rbias@ischool.utexas.edu |
Experiment 1
Instead of numbers, I’ll present CVC
(consonant-vowel-consonant) strings -- like
“NEH”.
10 CVCs, one at a time.
Presented visually.
Don’t have to remember them in order.
Pencils down.
Ready?
R.G. Bias | rbias@ischool.utexas.edu |
BOV
NAZ
TOL
RIJ
DIH
REN
WUK
CAQ
GOC
MEB
R.G. Bias | rbias@ischool.utexas.edu |
BOV
NAZ
TOL
RIJ
DIH
REN
WUK
CAQ
GOC
MEB
R.G. Bias | rbias@ischool.utexas.edu |
Experiment 2
Now, 10 new CVCs.
Same task -- recall them.
This time, after we read the 10th item,
we’ll all count backwards from 100 by 3s,
aloud, together.
Then when I say “Go,” write down as
many of the 10 CVCs as you can.
Pencils down.
Ready?
R.G. Bias | rbias@ischool.utexas.edu |
VAM
LUN
XOP
REH
WIV
CIT
JEG
KUC
ZOB
YAD
R.G. Bias | rbias@ischool.utexas.edu |
VAM
LUN
XOP
REH
WIV
CIT
JEG
KUC
ZOB
YAD
R.G. Bias | rbias@ischool.utexas.edu |
Experiment 3






Same as Experiment 2.
Yet 10 more CVCs.
Backwards counting.
Don’t have to recall them in order.
Pencils down.
Ready?
R.G. Bias | rbias@ischool.utexas.edu |
GEP
TIV
WOH
LUP
MAZ
SEX
KOL
RUC
NID
BIR
R.G. Bias | rbias@ischool.utexas.edu |
GEP
TIV
WOH
LUP
MAZ
SEX
KOL
RUC
NID
BIR
R.G. Bias | rbias@ischool.utexas.edu |
So here we’ve seen . . .




The Serial Position Effect (I hope)
STM (and the Recency Effect)
LTM (and the Primacy Effect)
The effect of novelty
R.G. Bias | rbias@ischool.utexas.edu |
Atkinson and Shiffrin Model of
Memory (1968)
R.G. Bias | rbias@ischool.utexas.edu |
STM?
 Miller’s (1956) “Magical Number 7 +/- 2: Some
limits on our capacity for processing information”
– Found we could hold only a limited number of items in
STM
– Realized that we could hold more “items” if we could
“chunk” them
– So, you might remember just 5 to 7 of these numbers:
53985389491041093847732
– But MORE of 555333999888555333888999
– And even more of 3333333333333333333333333.
(Bigger chunks!)
R.G. Bias | rbias@ischool.utexas.edu |
Note why we need a short-term
memory
 Sometimes we need to hold some things in
memory – keep them active and accessible -while we take in NEW information, to make
sense of whole, um, thing.
– To perform mental arithmetic.
– To read a sentence – you need to keep those early
words in mind to understand the semantics – the
meaning – of the whole sentence. (“The dog that
chased the cat bit the boy.”)
R.G. Bias | rbias@ischool.utexas.edu |
Some factors that influence
working memory capacity
 Meaningfulness of the material (and thus the
chunkability)
 Pronunciation time – it’s easier to recall
Burma Greece Tibet Iceland Malta Laos
than it is to recall
Switzerland Nicaragua Botswana Venezuela
Phillipines Madagascar
 Semantic similarity of the items (if I gave you 8
vegetable names you’d do better than if I gave
you 8 concrete nouns across various categories)
R.G. Bias | rbias@ischool.utexas.edu |
So . . . STM or Working Memory
 Transient - temporary encoding.
 Back-and-forth relationship with LTM: STM can contain information
from LTM to work on. Often, information in STM enters LTM.
 Direct access to STM contents.
 Holds information for current use only; called active memory;
primary memory - first stage of memory, as opposed to secondary
memory.
 Limited capacity: 7 +/- 2. It is a fundamental limitation on our mental
capacity.
 Rehearsal maintenance - as long as you rehearse items they can be
maintained indefinitely. But when attention shifts . . . .
 Chunk information to increase capacity - the capacity of STM varies
with the meaningfulness of the material. A chunk is a memory unit -STM capacity is not limited by a physically defined unit but by a
meaningfulness unit.
R.G. Bias | rbias@ischool.utexas.edu |
Baddeley’s (2000) model of
working memory
R.G. Bias | rbias@ischool.utexas.edu |
Baddeley’s model of working
memory (cont’d.)
 Phonological loop?
– Acoustic confusions. (You know your “inner voice.”)
 Visuospatial sketchpad?
– You retain both visual and spatial information.
– Look at a complex scene, gather visual information, establish
landmarks.
 Episodic buffer?
– Temporary storehouse where we gather and and combine info
from two above components. A way to combine info from
different modalities (vision and audition)
 Central executive
– Manages the back-and-forth with LTM
– Suppresses irrelevant info – related to attention.
R.G. Bias | rbias@ischool.utexas.edu |
LTM
 Comprised of 3 types of knowledge
– Semantic (declarative) memory – knowledge about
the world; “facts”
– Episodic memory – memory for events that happened
to you
– Procedural memory – how to do things
 Large (unlimited?) capacity
 Associative, multi-indexed
 Duration – perhaps a lifetime
– Forgetting; cued recall; recognition vs. recall
R.G. Bias | rbias@ischool.utexas.edu |
Craik and Lockhart (1972)
 Argued for a “levels of processing”
approach (or “depth of processing”)
 Predicts that you will recall of something
better if you processed it more deeply
– We’re three times more likely to recall a word
if we’ve earlier answered questions about it’s
meaning than if we’ve answered questions
about its physical appearance.
R.G. Bias | rbias@ischool.utexas.edu |
We recall things better . . .
 If we process them more deeply.
 If we relate the information to ourselves
 If we are asked to recall it in the same
context in which we learned it (encoding
specificity principle, or context-dependent
memory)
 If we react positively to the items (the
Pollyanna Principle)
R.G. Bias | rbias@ischool.utexas.edu |
So?
 So, the answer to “Can you remember a 30digit number?”, is . . . It depends. On what?
– Whether you hear or see the number.
– Whether the number is masked.
– Whether you have time to rehearse.
– Whether you can “chunk” the numbers.
– If there are any intervening tasks.
– How meaningful the number is.
– WHAT the number is.
So, what’s a usable interface?
It depends.
R.G. Bias | rbias@ischool.utexas.edu |
Resources
 Matlin, M. W. (2009). Cognition.
Hoboken, NJ: John Wiley and Sons, Inc.
 http://home.sandiego.edu/~taylor/stm.html
R.G. Bias | rbias@ischool.utexas.edu |
 Today’s song was “Remember” by John
Lennon.
 Why do you suppose we chose to play it
before THIS class?
R.G. Bias | rbias@ischool.utexas.edu |