Transcript What is Psycholinguistics - Linguistics @ HKU | Main

What is Psycholinguistics
Psycholinguistics investigates the mental
mechanisms underlying language
processing. (Cognitive)
How to perceive words and store them in the
mind, how to understand a sentence, how to
learn to read, how language and writing
systems influence mental organizations.
Psychological reality of linguistic aspects
Decode spoken language, speech
Characters
Words
Alphabetic
Logographic
Syllabary/syllables
Pictographic; Naxi nationality, Yunan
What is Psycholinguistics
Two Aspects:
Language Comprehension –how we
understand the meaning of words and
sentences (receptive process)
Language Production –how we speak and
use language (productive process)
Example: Language Production
• Language production is a process
from idea generation to language
expression.
• It is a mental process that is heavily
influenced by language users’ culture.
Example: Language Production
Idea: cross-cultural communication
• People using the same language (i.e.
English) but coming from different cultures.
• Example: Cultural differences in directness –
how explicitly and clearly do we say what we
mean.
• Case study: letters of recommendation for a
bright but immature student, Peter Gore. (By
John McCarthy)
Example: Language Production
British Professor
(least direct)
“Mr. Gore impresses one as very
intelligent. As to his maturity and
readiness for graduate study, I can say
very little, having had an opportunity to
observe him only under relatively
unfavorable conditions.”
Example: Language Production
American Professor
(intermediate directness)
“In my judgment, Gore is very intelligent.
During the time I have known him, I have
seen him grow in maturity; I hope and
expect that this will continue when he
begins graduate study.”
Example: Language Production
Australian Professor
(most direct)
“Peter’s brilliant, there’s no doubt about
that. But he’s a bit of a baby, with a lot of
growing up to do.”
Example: Language Production
Chinese Professor
(from Mainland)
(Ignore the fact)
“Peter Gore is a very smart student. He
was doing extremely well in my class. He
gets along well with everyone and is
respected by others.”
Example: Visual Word Recognition
When people encounter a printed word,
how do they identify it?
Properties of the word
 Visual or auditory (Modality)
 Orthographic –whether a word is constructed in a
legal way (e.g. “math” vs “mtah”)
 Phonological (syllable: /cat/; phoneme: /k/, /e/, /t/,
 Meaning
Example: Word Recognition
In identifying a written word,
 Visuo-orthographic analysis occurs.
(activate, activation)
 Is the meaning of a word accessed
automatically?
 Is the phonological information of a word
accessed automatically?
Example: Word Recognition
An Experiment:
Task: Speak out the color name of the stimulus you
will view. (red, blue, green)
Requirement: Complete the task as quickly and
accurately as possible.
Subjects, participants,
(The task was devised by Stroop, 1935 --the “Stroop task”.)
Example: Word Recognition
Possible results:
For color words (red, green, blue), when their
ink color is inconsistent with the meaning of
the words,
 Naming time is longer (i.e.response latency);
Responses are less accurate.
Example: Word Recognition

Why there is such an interference effect?
The mental lexicon
/blu:/
red
blue
*
red
The mental lexicon
/blu:/
red
blue
*
red
Example: Word Recognition

The above finding suggests that the
meaning of words is activated
automatically –people cannot
control the activation of meaning.

automaticity
Example: Word Recognition

What about the phonological information
of a written word in a silent reading task?
Is a word’s phonology activated in a task
that does not require reading aloud?
Example: Word Recognition

Another experiment:
Task: On each trial, you will first see a semantic
category name (e.g., “flower”). Following the
semantic category, you will see a target word
which may be an exemplar of the category
(e.g., “rose”). Judge if the target word you will
see is an correct exemplar of the category.
Example: Word Recognition
A servant
Example: Word Recognition
maid
Example: Word Recognition
Type of food
Example: Word Recognition
meet
Example: Word Recognition
Part of a mountain
Example: Word Recognition
peek
Example: Word Recognition
A flower
Example: Word Recognition
Rows (rose)
Example: Word Recognition
Possible results:
High “false” correct responses to
homophones of the exemplars.
Suggest that the meaning of words is
accessed via phonology.
flower
rose
/rouz/
rows
rows
Yes
(false)
Why We Study This Kind of Stuff?


Empirical, theoretical, not practical, unapplied
Research on normal readers’ word
identification processes provide a solid
basis for treating abnormal readers.
13%
4-6%
poor readers
developmental dyslexics (dyslexia)
Why We Study This Kind of Stuff?


Findings with normal readers indicate that
word meaning and phonology are activated
automatically.
Apply the same tasks to dyslexia. There is a
phonological deficit for dyslexics –they
cannot activate phonological information
obligatorily.
Why We Study This Kind of Stuff?

Hong Kong: Mother tongue education

Any scientific basis for this? Who ever
conducted scientific studies showing this is
feasible now?

USA: new school test design –New standard
China: new curriculum design

Research Methodology in
Psycholinguistics
1.
Reaction time (RT) approach
It measures people’s RT (response latency)
to a language stimulus. It includes many
on-line methods of studying people’s
language behavior continuously in a
laboratory setting
Infer the mental activity in terms of RTs.
dog
dog
/dawg/
Research Methodology in
Psycholinguistics
2. Memory and Classroom Approach
It investigates language behavior in
classroom, a more natural setting.
To study the developmental pattern of
children’s reading ability:


cross-sectional (grades 1 to grade 5)
longitudinal (a 5-year study)
Research Methodology in
Psycholinguistics
3. Eye movements Approach
Use the eyetracker to measure the position
and duration of people’s eye fixations upon
the text
It is a most reliable psycholinguistic
technique.
Research Methodology in
Psycholinguistics
How the Eyes Work?
When people read, the eyes do NOT move
continuously. Instead, the eye will “stop” on
some word for a brief period (150 to 500
milliseconds). This is called fixation.
Between the fixations are periods where the
eye moves rapidly. These rapid eye
movements are called saccades.
Research Methodology in
Psycholinguistics
To understand a sentence, the eyes
sometimes move back to some word, refixating it. These “backward” saccades are
termed regression.
Words that are fixated are in the fovea; words
surrounding the fixated words are in the
parafovea.
Research Methodology in
Psycholinguistics
A healthy body may seem reward enough for
. .
.
.
.
. .
177 196
175
244
302
112 177
most people. However, for all those who
. .
.
.
.
266
188
199
216
212
question the payoff, some recent research…
.
.
.
.
179
266
245
188
Research Methodology in
Psycholinguistics
How the Eyes Work?
Fixation
Saccades
duration
length (characters)
English
231 msec.
7.8
Hebrew
265 msec.
5.5
Chinese
300 msec.
2.0
Research Methodology in
Psycholinguistics
How the Eyes Work?
Information extracted from the parafovea aids in reading:
Reading rate is about 200 words per minute when only
the fixated word is visible on each fixation, but it is 300
words per minute when both the fixated word and the one
immediately to the right are visible on each fixation.
Research Methodology in
Psycholinguistics
4. Neurolinguistic Approach
It studies the brain mechanism for language
functioning –where is language functioning
localized in the brain?
Lesion study –using brain-damage patients
 Functional brain imaging study –using the
intact human brain

Research Methodology in
Psycholinguistics
Left
hemisphere
cortex
Right
hemisphere
Research Methodology in
Psycholinguistics
Basic Neuroanatomy:



The outer layer of the brain –cerebral cortex
Hidden underneath the cortex are
subcortical parts of the brain
The left and right hemispheres are
connected by a band of nerve fibers –
corpus callosum
Research Methodology in
Psycholinguistics
Basic Neuroanatomy:

An important feature of the human nervous
system is that each cerebral cortex is
connected to the opposite side of the body.
This is termed contralateral connections.
(Same-side connections are very weak.)
Research Methodology in
Psycholinguistics

Split-brain patients –those who have a
damaged corpus callosum but an
undamaged brain.
Research Methodology in
Psycholinguistics
Research Methodology in
Psycholinguistics

Results:
The left hemisphere is a language
hemisphere. (dominant).
Research Methodology in
Psycholinguistics

Brain Imaging Techniques
Language processing requires energy.
Brain imaging techniques depend on the
fact that working brain tissue calls more
blood its way and consumes more
glucose.
Research Methodology in
Psycholinguistics
Research Methodology in
Psycholinguistics
“Brain Imaging ” -- visualize the activity of
the intact human brain
• PET (positron emission tomography)
Subjects are injected with glucose that has
been tagged with a radioactive substance;
through this, brain images can be got
indicating which regions of the brain have the
greatest blood flow are are using the most
energy.
Research Methodology in
Psycholinguistics
Washington University at St. Louis:
1986: Fox et al., Nature
1988: Fox et al., Science
1988: Petersen et al., Nature
1988: Posner et al. science
Research Methodology in
Psycholinguistics
• fMRI (functional magnetic resonance imaging):
When subjects perform a task (e.g., reading), neural
activity in specific areas of the brain increases. This
results in greater need for glucose and oxygen, both of
which are met by increasing blood flow. There is a small
difference in magnetic susceptibility (a property of
molecules) between oxygenated hemoglobin and deoxygenated hemoglobin. With increased blood flow to
activated brain areas, there is a change in the proportion
of oxygenated to de-oxygenated hemoglobin. This
difference can be detected in the scanner.
Research Methodology in
Psycholinguistics
1992: K.K. Kwong et al. (PNAS)
S. Ogawa et al. (PNAS)