Langston,
Cognitive Psychology, Notes 12 -- Language--Meaning
I. Goals:
A. Where we are/themes.
Meaning:
B. Literal.
C. Inferences.
D. Figurative Language.
E. Pragmatics.
Understanding:
F. Readers’ knowledge.
G. Working memory revisited.
H. Outline of a basic discourse model.
I. Mental models.
J. Wrap-up.
II. Where we are/themes. I have two goals for this
lecture:
Meaning: When we talk about the “meaning” of a sentence, it can
actually be represented at multiple levels. What we'll do is look
at the kinds of information represented at each level. We'll
start
with literal. Then we'll talk about going a little beyond literal
by adding information to the representation. Then we'll go way
beyond
literal by looking at figurative language (the meaning is different
from
the words). Finally, we'll talk about pragmatics (the meaning
isn't
in the words at all).
Understanding text. When we're through with meaning, we're going
to move on to talk about extracting the meaning from texts. What
do we have to talk about? We have to extract the information, we
have to make some sort of representation, and we have to hook up the
ideas
in that representation. We need to store that away so we can
recall
it later, and we need to elaborate it with inferences.
What you're going to see will look a lot like two lectures piled
together.
That's because it is. The theme of this unit is to take all of
the
work we've done and integrate it to understand an interesting question.
Meaning: What is the meaning of a sentence? This
is a hard concept to define, and a hard concept to study. To make
it less complicated, I'm going to divide it into four parts.
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III. Literal meaning. This is what the sentence
is about in the strictest sense. This kind of meaning can be
broken
down as well.
A. Verbatim meaning: Basically, memorize the text.
You don't process it or try to understand it, just memorize it.
This
type of meaning representation is very poor. In some contexts
this
is all you have to rely on, so you will see people form verbatim
representations.
Usually, this is only used for rote memorization. If you think
about
the Star Spangled Banner (if you happen to know it) the meaning isn't
really
what you're reciting, it's the words, cued one from the other like a
behaviorist
sentence. The things whose meaning you understand aren't usually
remembered word-for-word.
B. Deep structure: It's a fact that people remember the
gist of what they read better than the exact words. One idea for
what the gist might be is to remember deep structures as in
transformational
grammar. So, if you hear “Alice plays the tuba” you remember
something
like “Alice play tuba”, and if you hear “The tuba was played by Alice
you
remember “Alice play tuba + passive”. The “+ passive” part refers
to the fact that the sentence you heard was in the passive voice,
otherwise,
you couldn't tell that from the representation. There's evidence
that when you have people recall sentences, they generally forget
transformations
more than meaning. We saw a little of this last time.
C. Propositional representation. Propositions are like
the idea units in a text. For example, the structure of “The
professor
delivers the boring lecture” would include:
P1: Exists(professor)
P2: Exists(lecture)
P3: Boring(P2)
P4: Deliver(P1, P2)
We'll see a more formal propositional system a little later.
Evidence:
1. That you go beyond verbatim representation:
Sachs (1967) presented a story about telescopes. During reading,
if you test immediately after a sentence, people recognize changes in
the
surface structure of the sentences as readily as changes in
meaning.
After 80 syllables, however, people recognize changes in meaning, but
not
changes in surface structure. Sentence (1) below is the
original.
After 80 syllables, (1) - (3) are all recognized at about the same
percentage.
(1) He sent a letter about it to Galileo,
the great Italian scientist.
(2) He sent Galileo, the great Italian
scientist,
a letter about it.
(3) A letter about it was sent to Galileo,
the great Italian scientist.
(4) Galileo, the great Italian scientist,
sent him a letter about it.
This finding is usually interpreted as demonstrating that you retain
the basic ideas more than the exact words.
2. That you have propositions:
Many studies show that what people forget from sentences tend to be
whole propositions. Furthermore, varying the number of
propositions
per sentence is a much more effective way of increasing the difficulty
of a text than varying the number of words.
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IV. Inferences. Inferences go beyond literal meaning
by adding something to the representation of the text that wasn't in
the
text. To see what an inference is, try the demonstration.
Demonstration: Read these two sentences. To
understand
how they relate, you have to make an inference along the lines of
“riding
a bike is a way to lose weight.” In general, making inferences is
so easy that you probably don't even know you're doing it.
(5) Diane wanted to lose some weight.
(6) She went to the garage to find her bike.
I'll present a scheme for classifying inferences along four dimensions.
A. Logical vs. pragmatic inferences: Some inferences are
guaranteed to be correct (if you form them). So, if you hear
“Todd
has six apples, he gave three to Susan”, it's safe to infer that Todd
has
three apples (logical inference). On the other hand, some
inferences
are likely, but not guaranteed (pragmatic). So if you hear “Todd
dropped the egg”, you don't know for sure that it broke (but it
probably
did).
B. Forward vs. backward: Some inferences are made in
advance.
For example, if you hear “John pounded the nail” and infer “John used a
hammer,” it's forward. Other inferences are made about past
things.
For example, if you read “John pounded the nail. The handle broke
and he smashed his thumb,” you need to infer “hammer” to figure out
what
handle broke. Backward inferences are generally called bridging
because
they build a bridge between two parts of the text to explain how you
get
from one to the other. Forward inferences are usually elaborative
because they elaborate on the text but aren't strictly necessary.
C. Type of inference: There are five types here:
1. Case-filling: In your case-role grammar you can infer
parts that are missing. For example, if you hear “Father carved
the
turkey” you can fill in the instrument (like knife).
2. Event-structure: If you read “The actress fell from
the 14th floor balcony” you might infer the consequence (she
died).
Or, you might infer a cause (she slipped). These are things that
flesh out the structure of an event.
3. Parts: If I say “Carol entered the room. The X
was dirty”, you might infer “the room has an X.” Usually, these
are
required to make sense of a text. For example, if you read “He
poured
the tea and burned his hand on the handle” you need to infer a teapot
handle
to make sense of it.
4. Script: People have scripts for prototypical
event-sequences
(like going to a restaurant). Script inferences are when they
fill
in missing events with items from the script.
5. Spatial/temporal: You can infer relationships between
items in a text. For example, if I say “B is to the left of A”,
you
might infer “A is to the right of B.”
D. Implicational probability: How strongly is the inference
implied by the text. Some things are much more likely than
others.
For example, floors are more likely in rooms than chandeliers.
When we look at our model of understanding we'll see that inferences
have a major role to play.
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V. Figurative language. The meaning is completely
different from the words used to convey it. I'll just list some
of
the more common types.
A. Metaphor: “John is a pig” You know John isn't
actually a pig, the meaning somehow relates features of pigs to
features
of John.
B. Idioms: “Spill the beans.” It's like a
conventionalized
metaphor. In terms of comprehension, it's treated like a big
word.
For example, “spill the beans” = “tell a secret.”
C. Metonymy: “Washington and the Kremlin are finally
talking.”
Let some aspect stand for the whole. For example, we let the fact
that the US government is in Washington stand for the whole government.
D. Colloquial tautologies: “Boys will be boys.” It's
a kind of metonymy where some feature is highlighted. It's
usually
negative (as in “business is business”), but for objects it's also
indulgent.
So, you'll hear “boys will be boys”, but not “rapists will be rapists.”
E. Irony/sarcasm: The words are used to express a situation
that's actually opposite from the words. For example, if
someone's
lounging on the couch and you come in and say “Boy, you're working
hard.”
Figurative language represents a special case for reading, because
we have to get from one set of words to a different set of
meanings.
How it's done is an interesting challenge for our methodology.
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VI. Pragmatics. Speaker and hearers' background
beliefs, understanding of the context, and knowledge of the way
language
is used to communicate. Note that none of this stuff is literally
in the message. Consider:
(7) The councilors refused the marchers a
parade permit because they feared violence. (who fears?)
(8) The councilors refused the marchers a
parade permit because they advocated violence. (who advocates?)
The information about who fears and who advocates comes more from your
knowledge about councilors and marchers, not as much from the sentence.
I'm going to lump a lot of diverse language activities under this
umbrella
for want of a better place to put them. The thing they have in
common
is that the meaning is derived as much from external factors as from
the
message.
A. Presuppositions: An assumption or belief is implied
by the choice of a particular word. Consider:
(9) Have you stopped exercising regularly?
(10) Have you tried exercising regularly?
“Stopped” implies that you used to exercise, “tried” implies that you
don't exercise. It's possible that in some contexts this will
even
lead to a person being insulted.
B. Speech acts: The effect of the message is different
from its literal content. There are 3 parts:
1. The locutionary act: The utterance.
2. The illocutionary act: What's intended by the speaker.
3. The perlocutionary act: The effect.
If I said “Can you shut the blinds?”: L = “Are you able to shut
the blinds?”, I = “Please shut the blinds”, P = someone shuts the
blinds.
Speech acts can take numerous forms:
1. Statement: “There's a bear behind you.”
2. Command: “Run!”
3. Yes/No question: “Did you know there's a bear behind
you?”
4. Wh- question: “What's that bear doing in here?”
The form can have an impact on the perlocutionary act.
Understanding: What does it mean to understand?
Again, hard to say. Try this demonstration.
Demonstration: Read the two passages. One should
seem easy to understand, one should be hard. By the end of this
unit,
we should be on our way to quantifying why that is.
"Weighing less than three pounds, the human brain in its natural state
resembles nothing so much as a soft, wrinkled walnut. Yet despite
this inauspicious appearance, the human brain can store more
information
than all the libraries in the world. It is also responsible for
our
most primitive urges, our loftiest ideals, the way we think, even the
reason
why, on occasion, we don't think, but act instead. The workings
of
an organ capable of creating Hamlet, the Bill of Rights, and Hiroshima
remain deeply mysterious."
"On the other hand, there may be portions of this task which can be
formulated without reference to numerical relationships, i.e. in purely
logical terms. Thus certain qualitative principles involving
physiological
response or nonresponse can be stated without recourse to numbers by
merely
stating qualitatively under what combinations of circumstances certain
events are to take place and under what combinations they are not
desired."
As we do this unit, we'll focus on readers’ knowledge, because what
you already know is a big influence on what you understand. Then,
we'll look at a model of understanding to see how it might work.
There will be several parts to that.
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VII. Readers’ knowledge. You have a lot of world
knowledge that you can bring to bear when reading. That knowledge
will greatly influence how well you understand the text. One type
of knowledge is script knowledge. For a lot of overlearned event
sequences, you know what typically happens. We talked about going
to the doctor's office before. When you're trying to understand a
story, one thing you're doing is matching it to a script. If you
know a lot about doctors, you can fill in details from the story to
improve
comprehension. You can also use the script to help you remember
the
story later. There are also scehmas. These are knowledge
structures.
For example, you should be developing a cognitive psychology
schema.
How can these affect comprehension?
A. A prior context is one way to improve comprehension.
Basically, knowing which script (or schema) to apply will help you
understand.
Demonstration: One of these passages follows a typical
script, one follows a schema. Read this passage. Brief
retention
interval. Write down all you recall. Memory should be
poor.
Now, the title is “suppressed so my demonstration works.”
Recall.
Does it help? Try reading it again with the title.
Recall.
Does it help?
A second try: Half get “title suppressed” half don't.
Everyone
read the passage and recall. Who gets more?
What usually happens is that prior context helps with memory because
it gives you a way to organize the information. Without a
context,
it's very hard to make sense of the texts, and memory is poor.
B. A problem is: If all you're doing is remembering the
script, how do you tell individual events apart? An easy answer
is
that you usually don't. What did you have for breakfast a year
ago
today? Most people have no idea how to answer this
question.
In experiments, people will frequently “remember” things that are
typical
of a script, but not in the text they read.
Demonstration: Half the people read about Guy 1, half
read about Guy 2. After a longish retention interval, the Guy 2
people
are more likely to falsely recognize sentences about Guy 2 than the Guy
1 people.
Half the people read about Guy 1, half read about Guy 2. Then,
after a week, they were asked to recognize statements. The Guy 2
group was more likely to falsely recognize statements like “sorry, it's
a secret.” The point is that when recalling, prior knowledge is
integrated
with what you are learning. To the extent you have prior
knowledge,
reading isn't all that hard. When the knowledge is missing,
reading
gets tougher.
C. It's not just scripts and prior context that can provide the
necessary knowledge to make a text comprehensible.
Demonstration: Read this passage. Now, try it with
the picture. It should make more sense and be easier to remember.
The point of this section so far is clear. If you have something
to use as the foundation of your representation, good. If not,
it's
hard. Some of the material for this class should present you with
these kinds of problems because of a lack of prior knowledge.
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VIII. Working memory revisited. As you've probably
noticed, working memory plays a big role in almost every model of
comprehension,
at every level. How does it affect language comprehension?
It acts as a limit on how much you can hold at once.
When you get an item that you want to include, you have to gather some
activation (akin to “mental energy”) that you can use to represent
it.
Putting something in working memory takes mental effort. If you
don't
work at it, it won't happen. Unfortunately, the amount of mental
energy that you have at your disposal is fixed (when we talk about
working
memory capacity, that's the capacity).
Let's say you're processing this sample of text:
The plate is on the table.
The spoon is left of the plate.
The fork is behind the spoon.
The cup is right of the fork.
Let's further assume that your working memory capacity is three things
(plus processing load). (This will make more sense if you follow
along with the figure.) When you get the first proposition, you
can
give it all of your storage capacity. When the next proposition
comes
in, you have to steal some activation to represent it. So, they
both
get in, but they're each half as strong as the first one was.
Then
the third proposition comes in. You steal some more activation,
and
put it in.
When the fourth proposition comes along, you're out of juice.
Now, when you steal activation, something has to go.
Working memory limitations are a driving force behind theories of
language
comprehension. Last time we discussed parsing strategies like
late-closure
to ease the burden. The models of understanding also have working
memory limitations.
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IX. Outline of a basic discourse model. The basic
problem in text comprehension is that the meaning of a text is more
than
the meanings of its sentences. Somehow, you have to connect
information
in the sentences into a coherent structure that is the “meaning” of the
text. The Kintsch and vanDijk (1978) model illustrates all of the
basic parts of this process.
A. There are four main steps in comprehending texts. They
are:
1. Turn the text into propositions. There's a fully
developed
system for this. Here's an example of a basic proposition, just
to
get the flavor:
(P1 (WANTS JOAN APPLE))
The parts:
a. P1: This is the proposition number. Propositions
can be embedded in propositions, as in (P2 (TIME:IN P1
YESTERDAY)).
The numbering system acts as an embedding shorthand.
b. WANTS: A relation. The word is in all caps to
indicate that it's a concept, not a word. So, propositions are
supposed
to be in the “language of thought,” not tied to a particular
language.
WANTS could just as easily be AS1295D.
c. JOAN APPLE: Arguments. These are what the relation
is about. Some relations need two arguments, some need just
one.
The number of arguments is based on the same considerations we
discussed
when we talked about verbs and cases. It's unusual to say “I
gave”
because “give” normally requires an object to be given.
The first step is to take an entire text and turn it into propositions.
2. Arrange the propositions into a text base: An organized
representation of the text (but only a local representation, meaning it
covers relationships between ideas that are close together). It
will
look a lot like our phrase markers from last week, but we're connecting
concepts and not syntactic categories.
Some propositions appear more often (they're important to the story
so they stay in working memory).
3. Use world knowledge to form global concepts (akin to
identifying
the main ideas).
4. Form a macrostructure: The relationships between the
units in the text base. Essentially, connect the smaller trees
into
a super-tree. World knowledge helps a lot with this as well.
Demonstration: To illustrate these concepts, look at these
samples of text. The one that's locally and globally consistent
should
be easy to understand because you can connect each new sentence to an
old
sentence, and there's a global structure. The one that's locally
inconsistent stays on a topic, but connecting each sentence is hard
because
inferences are required. The last one is easy to do locally, but
has a problem in its macrostructure. In general local problems
are
harder for readers than global problems. In fact, readers usually
don't notice global problems. The model takes this into account.
Locally and globally consistent
George wanted to run in a marathon.
Running requires a lot of energy, and this energy can come from
carbohydrates.
Spaghetti has a lot of carbohydrates, so George learned how to make
spaghetti.
Eating spaghetti helped George have the energy he needed to finish
the marathon.
Locally inconsistent
Diane wanted to lose some weight.
She went to the garage to find her bike.
Diane's bike was broken and she couldn't afford a new one.
She went to the grocery store to buy grapefruit and yogurt.
Globally inconsistent
Tammy was standing inside the health spa waiting for her friend.
She had just completed an exhausting workout.
Tammy's workout usually included a half hour of aerobics and an hour
of weight training.
Today, Tammy had doubled her aerobics time.
Tammy saw her friend and went into the health spa to greet her.
B. Some additional notes on the model:
1. Readability is characterized by properties of the text and
properties of the reader. For example, if the text is well
constructed,
but your memory is low, then you'll have a hard time building
structures.
Or, if the text is poor, but memory is high, you'll still struggle.
2. How do they test this model? They present the passages
to the model and look at its memory. The model's recall of a text
is based on how often a proposition was held over in working memory,
how
related propositions are to one another, how easy it was to form
structures,
etc.
They also present these passages to human participants and look at
their recall. If people tend to remember similar propositions in
a similar order, that's evidence that the model is using a similar
process.
3. This model has all the parts:
a. Levels of representation (we talked about this in the last
unit).
b. Limited working memory capacity.
c. Strategies to choose what to remember.
d. Influences of readers’ knowledge.
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X. Mental models. So far, our readers are extracting
propositions, building local structures, identifying topics, and making
global structures. Is there anything else going on?
Yes.
In addition to all of this, readers are forming mental models of the
events
in a text. A mental model is a representation of what the text is
about, not the text itself. So, it goes beyond propositions (a
representation
of the text).
A. Where is it? Remember that we talked about divisions
in working memory, and two main branches. You have an
articulatory
loop and a visuo-spatial scratchpad. The loop holds auditory
information
(either from hearing speech or recoding written text). The
sketchpad
is for images, processing pictures, and doing spatial things like
moving
your eyes across the page and processing visual features of text.
It's not so much a place as a kind of mental energy devoted to spatial
processing. All of the stuff we've discussed so far goes on in
the
loop, the mental model is in the sketchpad.
B. What do I mean by a model? Read the first two sentences
about turtles and logs. They both describe the same
situation.
If you read the first one and I give you the second one to verify, what
will happen? Now, look at the second two. They describe
different
situations. If I give you the first one and ask you to verify the
second one, what will happen?
(11) Three turtles rested on a floating log
and a fish swam beneath them.
(12) Three turtles rested on a floating log
and a fish swam beneath it.
(13) Three turtles rested beside a floating
log and a fish swam beneath them.
(14) Three turtles rested beside a floating
log and a fish swam beneath it.
The difference in terms of propositions is very slight. In fact,
the difference that distinguishes the sentences in the two situations
is
the same. So, there must be some additional level of
representation
that explains this. That's the mental model.
C. What do mental models do? One thing is keep information
foregrounded (show you that it's with the topic and should remain in
working
memory). Glenberg, Meyer, and Lindem (1987) demonstrated
this.
People read texts like this sample. At some point, they saw a
word
and had to say if that word was in the text. The trick was that
the
item could sometimes be associated with the main character (so it goes
where the main character goes) and other times dissociated (the
character
goes somewhere, the item stays behind). Associated items should
stay
foregrounded because they might come up again. Dissociated items
can usually be forgotten safely. A demonstration of this
experiment
is available on my software page.
If readers are forming a mental model, then associated items would
be near the character in the model, and dissociated items would be far
away. Being near should facilitate responding to the test.
If you look at the graph of the data, you can see that that
happens.
Associated items are more readily available after a one sentence delay
than dissociated items.
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XI. Wrap-up. What we've done is looked at how all
of our cognitive psychology tools could be brought to bear on
understanding
what you read and defining the meaning of what you read.
Obviously,
there's still more to it. But, this gives you an idea of how the
representations and processes discussed so far can aid in comprehension
of complex cognitive activities. For more, take the language
class
in the fall.
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Cognitive Psychology Notes 12
Will Langston
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